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EK-SZ200-UG-B01

May 1993

100 pages

Original

0.7MB

Document:	DEC RAID Subsystem User's Guide
Order Number:	EK-SZ200-UG
Revision:	B01
Pages:	100
Original Filename:

OCR Text

DEC RAID Subsystem
User’s Guide
Order Number: EK–SZ200–UG–B01

Revision/Update Information:

Digital Equipment Corporation
Maynard, Massachusetts

This new document supersedes the
DEC RAID Subsystem User’s Guide,
Version 1.0.

May 1993
First Printing, November 1992
The information is this document is subject to change without notice and should not be construed
as a commitment by Digital Equipment Corporation. Digital Equipment Corporation assumes no
responsibility for any errors that may appear in this document.
Restricted Rights: Use, duplication, or disclosure by the U.S. Government is subject to restrictions
as set forth in subparagraph (c)(1)(ii) of DFARS 252.227-7013, or in FAR 52.227-19 or FAR
52.227-14, Alt. III, as applicable.
© Digital Equipment Corporation 1993.
All Rights Reserved.
Printed in the U.S.A.
The equipment described in this manual generates, uses, and may emit radio frequency energy.
The equipment has been type tested and found to comply with the limits for a class A computing
device pursuant to Part 15 of FCC Rules, which are designed to provide reasonable protection
against such radio frequency interference when operated in a commercial environment. Operation
of this equipment in a residential area may cause interference, in which case the user at his own
expense may be required to take measures to correct the interference.
The postpaid READER’S COMMENTS form on the last page of this document requests the user’s
critical evaluation to assist in preparing future documentation.
The following are trademarks of Digital Equipment Corporation:
BA350, DEC, DECnet, DECnet–DOS, DECserver, DECstation, DECwindows, OpenVMS,
StorageWorks, VAX, VAXcluster, VAX DOCUMENT, VAXstation, VMS, VT, and the DIGITAL logo.
The following are third-party trademarks:
ASPI is a registered trademark of Adaptec, Inc.
DPT, SmartCache, and SmartROM are registered trademarks of Distributed Processing Technology.
Intel is a registered trademark of Intel Corporation.
MS–DOS and Microsoft are registered trademarks of Microsoft Corporation.
Novell and NetWare are registered trademarks of Novell, Inc.
RAID Manager is a trademark of NCR Corporation.
SCO is a registered trademark of The Santa Cruz Operation, Inc.
UNIX is a registered trademark of AT&T.
Windows is a trademark of Microsoft Corporation.
X Window System is a trademark of the Massachusetts Institute of Technology.
All other trademarks and registered trademarks are the property of their respective holders.

This document was prepared using VAX DOCUMENT, Version 2.1.

Contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1 Product Description
1.1
1.2
1.2.1
1.2.2
1.3
1.3.1
1.3.2
1.3.3
1.3.4
1.3.5
1.4

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Product Highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Array Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Subsystem Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Product Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data Reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Redundancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Flexibility and Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1–1
1–3
1–3
1–3
1–3
1–3
1–4
1–4
1–4
1–5
1–5

2 DEC RAID Subsystem Component Descriptions
2.1
Description of the SZ200 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1.1
BA35X-VA Vertical Mounting Kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1.2
BA350-EA Shelf . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1.3
HSZ10-AA Controller (Disk Array Controller) . . . . . . . . . . . . . . . . . . .
2.1.3.1
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1.3.2
Firmware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1.3.3
Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1.4
System Building Blocks (SBBs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2
Expansion Unit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3
DEC RAID Utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.4
Enhanced SCSI Driver Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.5
SCSI Interconnects/Host Adapters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2–1
2–1
2–2
2–2
2–3
2–4
2–4
2–4
2–5
2–5
2–5
2–5

3 RAID Overview
3.1
3.1.1
3.1.2
3.1.3
3.1.4
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5

What Is a Disk Array? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Description of RAID 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Description of RAID 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Description of RAID 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Description of RAID 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Key Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Array Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Logical Units (LUNs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Drive Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Drive Ranks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Partitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–1
3–2
3–3
3–4
3–5
3–6
3–6
3–6
3–7
3–7
3–7

iii

3.2.6
3.2.7

Reconstruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Regeneration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–8
3–8

4 SZ200 Base Configuration
4.1
4.2
4.3
4.4
4.5

SCSI IDs for the DEC RAID Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . .
HSZ10-AA Controller Location and SCSI Address . . . . . . . . . . . . . . . . . . .
Physical Drive Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Logical Drive Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DWZZA-VA Bus Adapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–1
4–3
4–4
4–4
4–4

5 Basic Configuration Installation
5.1
5.1.1
5.1.2
5.1.3
5.1.4
5.1.5
5.2
5.3
5.4

Connecting to a Host . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Terminating the SCSI Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Connecting to a 16-Bit Differential Host/Adapter . . . . . . . . . . . . . . . .
Connecting to an 8-Bit Differential Host/Adapter . . . . . . . . . . . . . . . .
Connecting to an 8-Bit Single-Ended Host/Adapter . . . . . . . . . . . . . . .
Maintaining Bus Continuity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Verifying Cables and Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Powering On the Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Functional Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–1
5–1
5–2
5–2
5–3
5–4
5–5
5–6
5–6

6 Operations
6.1
DEC RAID Subsystem Monitoring Features . . . . . . . . . . . . . . . . . . . . . . .
6.1.1
Monitoring Through the HSZ10-AA Controller . . . . . . . . . . . . . . . . . .
6.1.1.1
LUN Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.1.1.2
Drive Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.1.2
Monitoring Through the StorageWorks Shelf . . . . . . . . . . . . . . . . . . . .
6.2
User Monitoring Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2.1
Monitoring Operation Using the DEC RAID Utilities . . . . . . . . . . . . .
6.2.2
Monitoring Operation Using LED Indicators . . . . . . . . . . . . . . . . . . . .
6.2.2.1
HSZ10-AA Controller LED Indicators . . . . . . . . . . . . . . . . . . . . . .
6.2.2.2
Power Supply LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2.2.3
Drive SBB LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.3
When and How to Replace a Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4
When and How to Replace Power Supplies and Blowers . . . . . . . . . . . . . .
6.4.1
Replacing a Shelf Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2
Replacing a Blower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.5
Reconstruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.6
Parity Check/Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.7
Upgrading Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6–1
6–1
6–1
6–3
6–4
6–4
6–4
6–5
6–5
6–7
6–8
6–10
6–11
6–11
6–12
6–13
6–14
6–15

7 Advanced Configurations
7.1
7.2
7.3
7.3.1
7.4

Modifying Basic Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Multiple Rank Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuration Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Expansion Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Recommended Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7–1
7–2
7–2
7–3
7–4

Expansion from a Single BA350-EA to a Single BA350-EA/Dual
BA350-SA Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.4.1.1
Pre-Reconfiguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.4.1.2
Shelf Reconfiguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.4.1.3
Post-Reconfiguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.4.2
Expansion from a Single BA350-EA to a Single BA350-EA/Quad
BA350-SA Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.4.2.1
Pre-Reconfiguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.4.2.2
Shelf Reconfiguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.4.2.3
Post-Reconfiguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.4.3
Expansion from a Single BA350-EA/Dual BA350-SA to a Single
BA350-EA/Quad BA350-SA Configuration . . . . . . . . . . . . . . . . . . . . . .
7.4.3.1
Pre-Reconfiguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.4.3.2
Shelf Reconfiguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.4.3.3
Post-Reconfiguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.5
Custom Expansions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7.4.1

7–5
7–5
7–6
7–10
7–11
7–11
7–12
7–16
7–17
7–17
7–18
7–22
7–22

8 Error Handling/Troubleshooting
8.1
8.2
8.3

Before You Begin Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Using the Troubleshooting Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If You Have Expanded Your DEC RAID Subsystem . . . . . . . . . . . . . . . . . .

8–1
8–1
8–3

A Physical Specifications
A.1
A.2
A.3
A.4

General Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Unit Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Environmental Stabilization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Environmental Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A–1
A–1
A–2
A–3

B Supported Options
C Operating System Support
D System Connections
Glossary
Index
Figures
1–1
1–2
2–1
2–2
3–1
3–2
3–3
3–4

SZ200 DEC RAID Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Logical View of the DEC RAID Subsystem . . . . . . . . . . . . . . . . . . . . .
SZ200 Base Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Physical Layout of the HSZ10-AA Controller . . . . . . . . . . . . . . . . . . . .
Conceptual Diagram of the DEC RAID Subsystem . . . . . . . . . . . . . . .
Diagram of RAID 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Diagram of RAID 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Diagram of RAID 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1–1
1–2
2–2
2–3
3–1
3–2
3–3
3–4

3–5
3–6
3–7
4–1
4–2
5–1
5–2
5–3
5–4
6–1
6–2
6–3
6–4
6–5
6–6
7–1
7–2
7–3
7–4
7–5
7–6
7–7
7–8
7–9
7–10

Diagram of RAID 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Diagram of a Regular LUN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Drive Partition Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DEC RAID Subsystem SCSI IDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Physical Drive Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Typical Y Cable Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BA350-EA and BA350-SA Combination Storage Array . . . . . . . . . . . .
Trilink Connector Midbus Connection . . . . . . . . . . . . . . . . . . . . . . . . .
Trilink Connector End-Bus Connection . . . . . . . . . . . . . . . . . . . . . . . .
LUN State Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LED Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Supply Status LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shelf Status LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacing a Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacing BA35X–MA Blowers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Single BA350-EA Shelf . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Single BA350-EA to Single BA350-EA/Dual BA350-SA Shelf
Reconfiguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Single BA350-EA to Single BA350-EA/Dual BA350-SA Drive
Reconfiguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BA350-EA and BA350-SA Combination Storage Array . . . . . . . . . . . .
Single BA350-EA Shelf . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Single BA350-EA to Single BA350-EA/Quad BA350-SA Shelf
Reconfiguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Single BA350-EA to Single BA350-EA/Quad BA350-SA Drive
Reconfiguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Single BA350-EA Shelf . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Single BA350-EA/Dual BA350-SA Shelf to Single BA350-EA/Quad
BA350-SA Shelf Reconfiguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Single BA350-EA/Dual BA350-SA Shelf Configuration to Single
BA350-EA/Quad BA350-SA Drive Reconfiguration . . . . . . . . . . . . . . .

3–5
3–6
3–8
4–2
4–3
5–2
5–3
5–4
5–5
6–2
6–5
6–7
6–9
6–10
6–13
7–6

Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Midbus Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
End-Bus Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Logical Unit Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Drive Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Summary of HSZ10-AA Controller LED Codes . . . . . . . . . . . . . . . . . .
Shelf and Single Power Supply Status LEDs . . . . . . . . . . . . . . . . . . . .
Shelf and Dual Power Supply Status LEDs . . . . . . . . . . . . . . . . . . . . .
Drive SBB Status LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Blower Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Expansion Paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting Systems Problems . . . . . . . . . . . . . . . . . . . . . . . . . . .
SZ200 General Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
StorageWorks Power Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

x
5–4
5–5
6–2
6–3
6–6
6–8
6–8
6–9
6–13
7–4
8–2
A–1
A–2

7–7
7–8
7–9
7–12
7–13
7–14
7–18
7–19
7–20

Tables
1
5–1
5–2
6–1
6–2
6–3
6–4
6–5
6–6
6–7
7–1
8–1
A–1
A–2
vi

A–3
A–4
B–1
B–2
C–1
D–1

Thermal Stabilization Specifications . . . . . . . . . . . . . . . . . . . . . . . . . .
Environmental Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disk Drives Supported . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Adapters Supported . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Systems Supported . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
System Connectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A–2
A–3
B–1
B–1
C–1
D–1

vii

Preface
Purpose
This guide introduces the DEC RAID Subsystem storage solution. It describes
available RAID features, packaging options, and configuration and operating
instructions. This guide serves as complementary documentation to the
StorageWorks™ documentation set.

Intended Audience
This guide is intended for customers of Digital Equipment Corporation, systems
administrators, and Digital Service Engineers responsible for installing and
maintaining the DEC RAID Subsystem products.

Structure
This guide is organized as follows:
Chapter 1, Product Description,
provides an overview of the DEC RAID Subsystem features and options.
Chapter 2, DEC RAID Subsystem Component Descriptions,
describes the DEC RAID Subsystem components including the base unit,
expansion units, utilities, driver support, interconnect, and host adapters.
Chapter 3, RAID Overview,
presents background information on disk array levels and components.
Chapter 4, SZ200 Base Configuration,
describes the SZ200 base unit and its physical/logical mappings.
Chapter 5, Basic Configuration Installation,
provides installation instructions including the StorageWorks documentation
references, host connections, and functional verification.
Chapter 6, Operations,
describes modes of operation and methods of monitoring the DEC RAID
Subsystem.
Chapter 7, Advanced Configurations,
discusses advanced configurations and expansion of the base unit.
Chapter 8, Error Handling/Troubleshooting,
provides error handling and troubleshooting guidelines.

Appendix A, Physical Specifications,
describes the physical, environmental, and performance specifications for the
DEC RAID Subsystem product.
Appendix B, Supported Options,
includes information regarding the disk drives and adapters supported by the
DEC RAID Subsystem.
Appendix C, Operating System Support,
contains information regarding the operating systems supported by the DEC
RAID Subsystem.
Appendix D, System Connections,
describes the type of connectivity for various systems to help you determine
cabling requirements for the systems.
Glossary,
defines terms associated with RAID and SCSI technologies that are used
throughout this guide and other related documentation.

Related Documents
The following is a list of documents that contain information related to this
product:
Document Title

Order Number

DEC RAID Utilities User’s Guide

EK–DECRA–UG

DEC RAID OpenVMS VAX Utility User’s Guide

AA–PYZLA–TE

DEC RAID OpenVMS VAX Utility Release Notes and Installation
Guide

AA–PYZUA–TE

DEC SCSI Tagged Command Queuing (TCQ) Driver for OpenVMS
VAX Release Notes and Installation Guide

AA–PXKGA–TE

HSZ10-AA Controller Site Preparation Guide

EK–HSZ10–IN

BA35X–VA Vertical Mounting Kit User’s Guide

EK–BA350SV–UG

StorageWorks Shelf Building Block Subsystem Configuration
Guide

EK–BA350–CG

BA350–EA Modular Storage Shelf User’s Guide

EK–350EA–UG

BA350–SA Modular Storage Shelf User’s Guide

EK–350SA–UG

Documentation Conventions
The following is a list of the conventions used in this manual.
Table 1 Conventions

boldface type

Indicates the first instance of terms being defined in text.

italic type

Indicates emphasis and complete manual titles.

1
Product Description
This chapter contains the following information:
•

Overview

•

Product highlights

•

Product attributes

•

General conclusions

1.1 Overview
The DEC RAID Subsystem is a modular, integrated, end-user RAID (Redundant
Array of Inexpensive Disks) solution based on the HSZ10-AA controller (disk
array controller). Figure 1–1 shows the SZ200 DEC RAID Subsystem.
Figure 1–1 SZ200 DEC RAID Subsystem

SHR-XR3000-VIF

Product Description 1–1

Product Description
1.1 Overview
The DEC RAID Subsystem provides you with a highly available and integrated
storage solution through the use of RAID technology, optional redundancy of key
components, value-added software utilities, and SCSI interconnect components.
Flexibility and performance result from your ability to select a RAID level that
best meets your application needs.
Logically, the subsystem looks like a large disk drive or multiple disk drives.
All RAID functionality is provided by a controller and associated firmware and
software. RAID management utilities are provided to allow you to configure and
control the subsystem as illustrated in Figure 1–2.
Figure 1–2 Logical View of the DEC RAID Subsystem
S
y H
s o
t s
e t
m

SW R
R

HW R

User Applications
Array Utilities
Enhanced SCSI Drivers
Host Adapters
SCSI Interconnect (s)

Host
O/S

Diff./Single Ended
Fast SCSI 8/16 Bit Wide
S
t
SZ200 o
r
Base a
Unit g
e

Array Controller (s)
Drives
Power Cooling
Options

P
a
c
k
a
g
e

BA350−S
Expansion

Storage
Rack

Drives

Floor
Mounted/
Rack
Mount

Expansion
Single Ended SCSI
Floor /
Power/
Options Rack
Cooler
Mount
SHR−XR3002−GRA

Physically, the DEC RAID Subsystem is based on the StorageWorks™ family of
products. The StorageWorks modular products provide configuration flexibility
by offering various shelf options, cabinet kits, and system building blocks (SBBs).
In addition, features such as hot swapping (meaning that the system does not
have to be powered down to perform swapping) of disks and power options are
achieved by means of carriers that interface directly with a rigid backplane.
This interface, along with optional redundant components, allows the removal
and replacement of key subsystem components without having to render the
system inoperable—a key attribute for systems that cannot tolerate down time.

1–2 Product Description

Product Description
1.2 Product Highlights

1.2 Product Highlights
This section includes the following information:
•

Array features

•

Subsystem features

1.2.1 Array Features
The following is a list of array features:
•

RAID levels 0, 1, 3, and 5

•

Five drive channels

•

Host array interface: differential 8/16-bit, 10/20 Mbyte per second, SCSI-2

•

Array channel interface: single-ended 8-bit, 5 Mbyte per second, SCSI-2

•

Array parity generation/checking and recovery with hardware assist

•

Array parity/data reconstruction with hardware assist

1.2.2 Subsystem Features
The following is a list of subsystem features:
•

Hot swapping drives and controller

•

Drive fault light indicators

•

Power supply and blower monitoring and indicators

•

Support for up to 35 disk drives

•

Redundant components

•

Modular configuration and upgrade paths

1.3 Product Attributes
This section includes information on the following attributes:
•

Data reliability

•

Redundancy

•

Data availability

•

Performance

•

Flexibility

•

Capacity

1.3.1 Data Reliability
Unlike a single SCSI disk drive solution, the DEC RAID Subsystem provides
dependable data reliability in the event of a disk failure. With a SCSI disk drive
solution, the user must replace the product and reconstruct the data through
backup media. This mechanism results in some user data loss since backup of
data is typically done at scheduled or infrequent intervals. Any activity that has
occurred since that last user data backup is not saved.

Product Description 1–3

Product Description
1.3 Product Attributes
In a DEC RAID Subsystem solution, there is no loss of data since redundant
elements provide the capability of continuing I/O activity despite the loss of a
drive and reconstruction of data back on the replaced drive. This means that data
is updated up to the second of failure and throughout the reconstruction process.

1.3.2 Redundancy
Most RAID products provide the feature of disk drive redundancy. However, what
is often neglected in a RAID solution is the redundancy of other key components.
This DEC RAID Subsystem provides optional redundancy of the following
components:
•

Power supplies

•

RAID disk array controllers (HSZ10-AA controllers)

•

Blowers

All components listed are removable and replaceable without needing to power
down the subsystem. These features contribute to making the subsystem fully
redundant.

1.3.3 Data Availability
One of the key attributes of the DEC RAID Subsystem is data availability. The
different RAID levels offer data protection at the drive level. In addition, the
redundancy designed into the StorageWorks packaging allows you to access data
even through other component failures.
For users whose livelihood depends upon minimal down time, these features are
critical.

1.3.4 Performance
The performance of a disk array depends on the environment and the I/O
workload. The following are general comments regarding array performance:
•

An array of smaller capacity drives can perform better than a single, largecapacity drive. This is due to the availability of multiple actuators, which
allow execution of I/Os simultaneously.

•

RAID 0 performs slightly better than a group of drives since it tends to
achieve load balancing across the drives.

•

The RAID 1 read performance is better than a group of drives since requests
can be served by either drive in a mirrored pair of disks. However, the RAID
1 write performance is slightly less due to the need to write to both drives.

•

RAID 3 is most appropriate in environments with large, sequential transfers.
It performs significantly better (four times better) than all the other
alternatives.

•

Like RAID 1, RAID 5 performs slightly better than a group of drives with
read requests. However, write performance is slightly impacted due to the
need to write parity information.

1–4 Product Description

Product Description
1.3 Product Attributes
1.3.5 Flexibility and Capacity
The disk array controller provides more capacity on a single-host adapter than
other data storage alternatives. The array controller acts as a multiplexer and
allows more SCSI disk drives to be connected to a single host connection.
The disk array controller has the flexibility to support different RAID levels and
classes of drives within the same array. This flexibility is important to meet the
various price, performance, and capacity options needed for different business
environments.
The combination of a modular packaging strategy along with an assortment of
cabinet and mounting options provides for a flexible, highly available storage
solution.

1.4 General Conclusions
The DEC RAID Subsystem provides a set of options from which users can choose.
The options vary the following features:
•

Data availability

•

Performance

•

Capacity

The flexibility in choosing various options to satisfy these requirements allows
you to meet your cost goals.
If your business cannot tolerate data loss or down time due to drive failures, then
you need the protection that disk arrays (RAID 1, 3, or 5) can provide.
Unlike multiple disks or RAID 0, the chance of losing data in a RAID 1, 3, or 5 is
extremely small even with a large number of drives.
In many businesses, the initial price of disk arrays versus multiple disks is offset
by the cost that would be incurred by a single-drive failure. This failure results
in the loss of data and a disruption of business operations.
For the same supported capacity, RAID 3 and 5 provide reliable storage at a
fraction of the drive price of RAID 1.
Disk arrays are the most cost-effective choice to meet the requirements of data
reliability, availability, performance, and capacity demanded in most business
environments.

Product Description 1–5

2
DEC RAID Subsystem Component Descriptions
This chapter contains a description of the DEC RAID Subsystem components as
follows:
•

SZ200 base unit

•

Expansion units

•

DEC RAID utilities

•

Enhanced SCSI driver support

•

SCSI Interconnects/Host adapters

2.1 Description of the SZ200
The SZ200 base unit is the basic building block for the DEC RAID Subsystem
(and part of the StorageWorks family of products). The SZ200 base unit includes
the following components:
•

BA35X-VA vertical mounting kit

•

BA350-EA shelf

•

HSZ10-AA controller (disk array controller)

•

System building blocks (SBBs)
Power
Disk drives
Adapters

For SZ200 physical specifications, refer to Appendix A. Figure 2–1 shows the
SZ200 base unit and identifies its components.

2.1.1 BA35X-VA Vertical Mounting Kit
The BA35X-VA vertical mounting kit is part of the StorageWorks family of
cabinet options. For the SZ200 base product, two BA35X-VA vertical mounting
kits are used to house the BA350-EA shelf. Each BA35X-VA kit has an ac
power controller that provides switch-controlled input voltages to the shelf power
supplies. Refer to the BA35X-VA Verticle Mounting Kit User’s Guide for more
detailed information.

DEC RAID Subsystem Component Descriptions 2–1

DEC RAID Subsystem Component Descriptions
2.1 Description of the SZ200
Figure 2–1 SZ200 Base Unit

HSZ10-AA
Controller
BA350-EA
Shelf
Disk Drive
SBB
Drive LEDs

BA35X Vertical
Mounting Kit

Power SBBs

SHR-XR3001-VIF

2.1.2 BA350-EA Shelf
The BA350-EA shelf is a double-width StorageWorks storage shelf option. The
BA350-EA shelf houses the HSZ10-AA controller and system building blocks
(power, drive, and adapter options). All components are plugged into a common
backplane.
The shelf provides six single-ended SCSI connectors. Five connectors are used for
RAID storage expansion from the HSZ10-AA controller to the BA350-SA shelves.
The sixth connector can be used for host interconnect adapters or storage devices.
Procedures for configuring and installing the BA350-EA shelf are discussed in the
BA350-EA Modular Storage Shelf User’s Guide.

2.1.3 HSZ10-AA Controller (Disk Array Controller)
The HSZ10-AA controller is an intelligent SCSI disk array controller based on
the Motorola MC68EC020 microprocessor running at 25 MHz. The HSZ10-AA
controller supports RAID levels 0, 1, 3, and 5. It supports expansion up to 35
devices (seven ranks).
The host SCSI channel is a synchronous/asynchronous/fast, 8/16-bit differential.
It supports SCSI-2 protocol. The host connection is made through a 68-pin,
high-density connector (J1) as shown in Figure 2–2. A second connector (J2) is
provided for daisy-chaining. SCSI term power is provided.
There are five array SCSI channels or interfaces that are made through
connectors J3, J4, and J5 as shown in Figure 2–2. Each interface is 8-bit,
single-ended synchronous/asynchronous SCSI-2. Active SCSI termination and
SCSI termination power are provided on the controller.

2–2 DEC RAID Subsystem Component Descriptions

DEC RAID Subsystem Component Descriptions
2.1 Description of the SZ200
Figure 2–2 Physical Layout of the HSZ10-AA Controller

J4
J7

J11
7.750
Switches
SW2 SW1

J18
J17

J10
J2

LED Display

12.500

Legend
J1
J2
J3
J4
J5
J6

68 pin host connector
68 pin host connector
2 array SCSI channels
2 array SCSI channels
1 array SCSI channel
subsystem signals
SW1
SW2

J7
J10
J11
J17
J18

drive fault signals (reserved)
RS232 port (reserved)
diagnostic port (reserved)
processor test port (reserved)
processor test port (reserved)

SCSI switches
manufacturing switches (reserved)
SHR−XR3003−GRA

2.1.3.1 Features
This section discusses the following features:
•

Controller features

•

Array features

HSZ10-AA Controller Features
•

68EC020 microprocessor running at 25 MHz

•

DRAM, 1 Mbyte for program and structures

•

EPROM, 256 Kbytes (expandable to 512 Kbytes) for diagnostics and start of
day code

•

EEPROM, 8 Kbytes for configuration and logging

•

68901 multifunction peripheral controller for timers, serial communications,
and interrupt control

•

Host SCSI target ID switch (4-bit)

•

Status LEDs (8-bit)

•

Self-test capability

DEC RAID Subsystem Component Descriptions 2–3

DEC RAID Subsystem Component Descriptions
2.1 Description of the SZ200
Array Features
•

SCSI host interface, 8/16-bit, synchronous, differential SCSI-2, 10/20 Mbytes
per second

•

SCSI array channels, 8-bit, synchronous, single-ended SCSI-2, 5 Mbytes per
second, active termination

•

Hot swapping controller and drive interfaces

•

RAID level 0, 1, 3, and 5

•

Hardware-assisted array parity generation/checking, recovery and
reconstruction

•

64 Kbyte read/modify/write buffer

•

Serial drive fault interface on each array channel

•

Blower and power supply monitoring

2.1.3.2 Firmware
The HSZ10-AA controller firmware is the part of the code that resides with
the controller’s EPROM. This code is responsible for controller diagnostics,
initialization, response to a limited set of SCSI commands, controller software
downloading/uploading, and passing control to the HSZ10-AA controller software.
2.1.3.3 Software
The HSZ10-AA controller software is the part of the code that is stored on the
array drives and must be uploaded into the controller’s DRAM prior to operation.
This code is responsible for all non-ROM operation of the board, including all
RAID algorithms and configurations, read and write operations, and advanced
SCSI functionality.
The software attempts to tolerate failures in the array that would cause loss of
data access. By maintaining multiple copies of the array software on multiple
drives, the controller software has as high availability as the user data. The
software also maintains configuration information in both EEPROM and on the
disk in order to tolerate the loss of one of these components.

2.1.4 System Building Blocks (SBBs)
All power, storage, and adapter options are mounted inside 3-1/2 inch modular
carriers that plug into slots in the BA350-EA shelf. A key feature is that each
SBB can be removed and replaced without removal of power to the system. In
addition, each SBB has visual status indicators so that it is easy to determine
whether devices are functioning properly.
Power SBBs
The SZ200 base unit uses two BA35X-HA universal ac input power supplies.
Additional power supplies can be added for power redundancy.
For more information on the StorageWorks power options, refer to the
StorageWorks Subsystem Shelf Building Block Configuration Guide.
Disk SBBs
The SZ200 base unit is configured with five 3-1/2 inch disk drives. For supported
disk options, refer to Appendix B.

2–4 DEC RAID Subsystem Component Descriptions

DEC RAID Subsystem Component Descriptions
2.1 Description of the SZ200
Adapter SBBs
The SZ200 unit provides a slot for a bus adapter option for connection to different
host types. For example, the DWZZA-VA bus adapter, which is a single-ended
differential SCSI converter, fits into the SZ200 unit.
Refer to Appendix B for supported adapter options.

2.2 Expansion Unit Description
Since the StorageWorks family of products is based on a building block concept,
expansion of the SZ200 base unit can be customized to allow for expansion.
Expansion of the BA350-EA shelf is done by using the BA350-SA shelf. The
BA350-SA shelf is a single-width storage module that holds up to seven 3-1/2 inch
devices. The shelf can be configured as either one or two SCSI buses.
Depending on the needed expansion, additional cabinet options are available
for installation of the shelf modules. For information on the available cabinet
options, refer to the StorageWorks Subsystem Shelf Building Block Configuration
Guide.

2.3 DEC RAID Utilities
DEC RAID utilities are applications, stand-alone, or operating system-specific
utilities that execute on the host system. These are used to configure, monitor,
diagnose and maintain the array subsystem.
Details on these utilities are operating system-specific and are described in the
DEC RAID Utilities User’s Guide.

2.4 Enhanced SCSI Driver Support
The enhanced SCSI drivers are part of the host adapter support. Enhanced SCSI
features are available in the SCSI drivers to better utilize the disk array. These
features include the following:
•

SCSI-2 tagged command queuing support

•

SCSI-2 logical unit support

•

Enhanced SCSI error handling capability

2.5 SCSI Interconnects/Host Adapters
The base unit can connect to a variety of qualified host adapters through various
SCSI interconnect schemes in order to meet the needs of SCSI users. Host
adapters currently supported are included in Appendix B.
The purpose of the SCSI interconnect is to provide fast/wide differential (FWD)
SCSI as a standard connection. This provides a direct interconnect into the
HSZ10-AA controller and uses the standard SCSI-3 P cable interconnect.
Other cable options provide resolution for the following:
•

Connections to single-ended devices

•

Connections to 8-bit devices initiator/targets with correct bus termination

DEC RAID Subsystem Component Descriptions 2–5

3
RAID Overview
This chapter contains information on RAID (Redundant Array of Inexpensive
Disks) levels, including the following:
•

What is an array?

•

Description of RAID 0

•

Description of RAID 1

•

Description of RAID 3

•

Description of RAID 5

3.1 What Is a Disk Array?
This section gives a brief definition of disk arrays and a description of the four
RAID levels currently supported by the DEC RAID Subsystem.
An array is a set of multiple disk drives and a specialized controller (an array
controller), which keeps track of how the data is distributed across the disk
drives.
Figure 3–1 shows a conceptual model of the DEC RAID Subsystem.
Figure 3–1 Conceptual Diagram of the DEC RAID Subsystem

Array Controller (HSZ10−AA)

Host
Adapter

1
2

SCSI−2
8/16 Bit Differential
10/20 MB/Sec

3
4
5

SCSI−2
8−Bit Single−Ended
5 MB/Sec

SHR−XR3004−GRA

RAID Overview 3–1

RAID Overview
3.1 What Is a Disk Array?
Data for a given file is segmented by dividing the data into segments and storing
it to the different drives in the array, rather than the data being written to a
single drive. A segment is a group of blocks that is continuous data which can
be stored on a disk drive. By using multiple drives, the array can provide higher
data transfer rates and higher I/O rates when compared to a single large drive.
Arrays can also provide data redundancy, so that no data is lost if a single drive
in the array fails. Depending on the RAID level, data is either mirrored or
striped. The RAID levels currently supported are RAID 0, 1, 3, and 5. RAID 1,
3, and 5 offer data redundancy.
Arrays are contained within an array subsystem or within an integrated array.
Depending on the model and on how you configure it, an array subsystem can
contain one or more arrays (referred to as logical units (LUNs) – see the
following sections for a description of arrays and logical units). Each logical unit
has its own characteristics (RAID level, logical block size, logical unit size, and so
on).

3.1.1 Description of RAID 0
RAID 0 stores data across the drives in the array one segment at a time, as
shown in Figure 3–2.
Figure 3–2 Diagram of RAID 0

SCSI−2
SCSI

Disk Array Controller
SCSI
SCSI
SCSI

SCSI

Data 1

Data 2

Data 3

Data 4

Data 5

Block 0−1
Block 10−11
Block 20−21
Block 30−31

Block 2−3
Block 12−13
Block 22−23
Block 32−33

Block 4−5
Block 14−15
Block 24−25
Block 34−35

Block 6−7
Block 16−17
Block 26−27
Block 36−37

Block 8−9
Block 18−19
Block 28−29
Block 38−39
SHR−XR3005−GRA

In Figure 3–2, a segment is defined as two blocks of 512 bytes each. Blocks 0 and
1 are written to drive 1, blocks 2 and 3 are written to drive 2, and so on until
each drive contains a single segment. Then blocks 10 and 11 are written to drive
1, blocks 12 and 13 to drive 2, and so on. (Note that segment zero is 0 blocks in
this figure, and therefore is not shown.)
The host system treats a RAID 0 array like a standard hard drive. RAID 0 errors
are reported in the same way as normal drive errors, and the recovery procedures
are the same as those used on a standard hard drive. For example, if a drive
fails, the array controller returns the same errors that occur during a read or
write retry failure.

3–2 RAID Overview

RAID Overview
3.1 What Is a Disk Array?
RAID 0 offers a high I/O rate, but is a nonredundant configuration, meaning
that there is no array parity information generated for reconstructing data in the
event of a drive failure. Therefore, there is no error recovery over and above what
is normally provided on a single drive. All data in the array must be backed up
regularly to protect against data loss.

3.1.2 Description of RAID 1
RAID 1 transparently mirrors data by striping segments across data drives and
mirrored data drives. Any time data is written to a drive, it is also written to a
mirrored drive without the system directly controlling the location of the mirrored
data as shown in Figure 3–3.
Figure 3–3 Diagram of RAID 1

Transparent Mirroring
SCSI−2
SCSI

Disk Array Controller
SCSI
SCSI

Data 1

Mirror 1

Data 2

Mirror 2

Block 0−1
Block 4−5
Block 8−9
Block 12−13

Block 2−3
Block 6−7
Block 10−11
Block 14−15

SCSI

SHR−XR3006−GRA

Traditionally, RAID 1 has been used for critical fault-tolerant transaction
processing. There is high reliability provided with the mirrored data and there
is high I/O rate (with small block size). However, RAID 1 is a more costly RAID
solution because it requires a mirrored data drive for every data drive in the
array.
In Figure 3–3, a segment is defined as two blocks of 512 bytes. Blocks 0 and 1
are written to data drive 1, while the mirrored data blocks 0 and 1 are written to
the mirrored data drive 1. Then data blocks 2 and 3 are written to data drive 2,
while the mirrored data blocks 2 and 3 are written to the mirrored data drive 2,
and so on.
If a drive fails in RAID 1 array, you can continue to use the array normally since
data from its mirrored drive is retrieved.

RAID Overview 3–3

RAID Overview
3.1 What Is a Disk Array?
A RAID 1 array is unique in that you can have more than one failed drive and
still use the data as long as there is only one failed drive in each mirrored pair.
For example, if you have a six-drive RAID 1 logical unit, you have three pairs.
If there is a drive failure in each pair, you can still access your data. It is still
recommended that you replace the failed drives as soon as possible because if a
second drive fails in a pair, all data on the logical unit is lost.

3.1.3 Description of RAID 3
RAID 3 transfers data in parallel to data drives and to one parity drive. The
result is an array that works best with large block transfers, but does not work
well for transaction processing.
In Figure 3–4, the segment is defined as 1 byte of data. The host transfers the
block of data, and the array controller stripes the data to the drives one byte at
a time. Byte 00 is written to drive 1, byte 01 is written to drive 2, byte 02 is
written to drive 3, byte 03 is written to drive 4, and the parity byte for bytes 00
through 03 is written to the parity drive.
Figure 3–4 Diagram of RAID 3

Parallel Disk Array (PDA)
SCSI−2
SCSI

Disk Array Controller
SCSI
SCSI
SCSI

SCSI

Data 1

Data 2

Data 3

Data 4

Parity

00
04
08
0C

01
05
09
0D

02
06
0A
0E

03
07
0B
0F

Parity
Parity
Parity
Parity
SHR−XR3007−GRA

Note
The logical block size for a RAID 3 logical unit varies, and is determined
by the operating system’s I/O and the number of data drives in the logical
unit. If the I/O block is 512 bytes, then the array controller can process
two times (for a three-drive logical unit) or four times (for a five-drive
logical unit) the I/O size of 512 bytes at a time. Remember that a RAID
3 logical unit has only two data drives in a three-drive logical unit, and
four data drives in a five-drive logical unit. This means that the logical

3–4 RAID Overview

RAID Overview
3.1 What Is a Disk Array?
block size of a three-drive logical unit is 1024 bytes, and 2048 bytes for a
five-drive logical unit.

If a drive fails in RAID 3 array, you can continue to use the array normally since
the array controller recalculates the data and parity blocks from the data and
parity on the operational drives.
For example, if drive 1 in Figure 3–4 fails, the array controller retrieves the data
by using the parity information for that segment and the data from drives 2, 3,
and 4 to reconstruct the data for drive 1. This process is repeated to reconstruct
each segment on a failed drive as needed, so you can continue to operate the
RAID 3 array.

3.1.4 Description of RAID 5
RAID 5 stores data across the drives in the array one segment at a time (a
segment can contain multiple blocks). It also writes array parity data, but the
parity data is spread across all the drives. The result is a transfer rate equal to
that of a single drive but with a high overall I/O rate as shown in Figure 3–5.
Figure 3–5 Diagram of RAID 5

SCSI−2
SCSI

Disk Array Controller
SCSI
SCSI
SCSI

SCSI

Data 1

Data 2

Data 3

Data 4

Data 5

Parity
Block 8−9
Block 16−17
Block 24−25

Block 0−1
Parity
Block 18−19
Block 26−27

Block 2−3
Block 10−11
Parity
Block 28−29

Block 4−5
Block 12−13
Block 20−21
Parity

Block 6−7
Block 14−15
Block 22−23
Block 30−31
SHR−XR3008−GRA

In Figure 3–5, a segment is defined as two blocks of 512 bytes. Blocks 0 and 1
are written in the first position on drive 2, blocks 2 and 3 are written on drive 3,
blocks 4 and 5 are written on drive 4, blocks 6 and 7 are written on drive 5, and
the parity data for the blocks in data segments 1, 2, 3, and 4 is written on drive
1, and so on.
If a drive fails in RAID 5 array, you can continue to use the array normally since
the array controller recalculates the data on the failed drive using data and
parity blocks on the operational drives.
For example, to recalculate data in data segment 4 in Figure 3–5 (the first
position on drive 5), the array controller would use the parity information from
drive 1 and the data from drives 2, 3, and 4 (data segments 1, 2, and 3) to
reconstruct the data. This process is repeated to reconstruct each block of the
failed drive as needed, so you can continue to operate the RAID 5 array.

RAID Overview 3–5

RAID Overview
3.2 Key Concepts

3.2 Key Concepts
The following sections define some of the terminology used to describe arrays.

3.2.1 Array Channels
Array channels are the SCSI-2 compliant buses on which the disk drives are
located. Each array channel is an independent SCSI bus.

3.2.2 Logical Units (LUNs)
A logical unit (LUN) is a grouping of drives. A logical unit has its own device
SCSI ID and LUN number. Each logical unit has its own array parameters (RAID
level, segment size, and so on). For most purposes, a logical unit is equivalent to
an array. See Figure 3–6.
Figure 3–6 Diagram of a Regular LUN
Channel 0

Channel 1

Channel 2

Channel 3

Channel 4

LUN 0

GROUP 0

GROUP 1

LUN 1

SHR−XR3009−GRA

A logical unit by most operating systems is treated as a single disk drive, so there
are usually no special requirements. Depending on the operating system, you
can create partitions or volumes in the same way you would treat an internal or
external hard disk.
A logical unit can be in various modes of operation, depending upon the RAID
level configuration.
Logical Unit modes of operation for nonredundant RAID level 0:
•

Optimal (All drives in the logical unit are functional.)

•

Dead (One or more drives in the logical unit are not functional.)

Logical Unit modes of operation for redundant RAID levels 1, 3, and 5:
•

Optimal (All drives in the logical unit are functional.)

•

Degraded (One drive in the logical unit is not functional.)

•

Dead (Two or more drives in the logical unit are not functional.)

3–6 RAID Overview

RAID Overview
3.2 Key Concepts
3.2.3 Drive Groups
A drive group is a set of from 1 to 10 drives that have been configured into one
or more logical units. A logical unit can be contained in only one drive group, and
all the logical units in a drive group must have the same RAID level and drive
type. Operating systems treat the logical unit (not the drive group) as a single
disk drive, sending I/O to it and retrieving I/O from it.
Most of the time, you should create only one logical unit in a drive group, so the
use of the terms logical unit and drive group are synonymous.

3.2.4 Drive Ranks
Drive ranks represent a numbering scheme providing information on the
maximum number of drives on every array channel. A one-rank system indicates
that there is a maximum of one drive per disk channel. A two-rank array
indicates that there is a maximum of two drives per disk array channel. However,
any array channel can have zero for its maximum number.
If you visualize the array channels as providing the user with a physical
limitation on the vertical number of planes in the array, then ranks provide
the limitation in a horizontal direction.
A rank is a physical grouping of drives that cannot be changed (unlike a
drive group, which is an arbitrary grouping of drives that can be changed by
reconfiguring). One rank of drives can contain up to five drives in the same
horizontal plane (in the multirank array) or vertical plane (in the single-rank
array). Drives in an array are identified by channel number and SCSI ID.
Channel numbers go from 1 to 5 within a rank. All drives in a rank must be on
different array channels. The drives are not required to have the same SCSI ID.

3.2.5 Partitions
A partition is a portion of each drive in a rank. The partition allows multiple
logical units on one rank of drives. This is useful if the host has a capacity limit
per logical unit.
Figure 3–7 is a conceptual diagram of the drive partition.

RAID Overview 3–7

RAID Overview
3.2 Key Concepts
Figure 3–7 Drive Partition Diagram

Channel 0

Channel 1

Channel 2

Channel 3

Channel 4

LUN 0
GROUP 0
LUN 1

LUN 2
GROUP 1
LUN 3

SHR−XR3010−GRA

3.2.6 Reconstruction
Reconstruction is done after a failed drive has been replaced in a RAID level 1, 3,
or 5 configuration. It is the process of rebuilding the data on the new drive using
data and parity from the other drives or the mirrored drive.

3.2.7 Regeneration
Regeneration occurs when data cannot be accessed from a drive in a RAID
level 1, 3, or 5 configuration. The inability to access data can be due to a drive
error or failure. Regeneration of data is done from the mirrored pair or from a
combination of the other drives and parity.

3–8 RAID Overview

4
SZ200 Base Configuration
The SZ200 subsystem is preconfigured at the factory and ready for use.
Preconfigured means that the disk array software has been installed, and
default RAID level and settings have been configured. The five drives have been
preconfigured to look as one logical unit.
The basic SZ200 configuration is as follows:
•

One HSZ10-AA controller

•

RAID level 5

•

Five drives—one drive per array channel

•

One logical unit

•

Segment size of 512 blocks

•

DWZZA-VA bus adapter (optional)

If this configuration does not meet your needs, it can be modified using the DEC
RAID utilities. Refer to appropriate the DEC RAID Utilities User’s Guide for your
operating system. If you need to expand your configuration to include additional
storage, refer to Chapter 7.

4.1 SCSI IDs for the DEC RAID Subsystem
Each device connected to the DEC RAID Subsystem is a SCSI device. A SCSI
device is a host computer adapter, or a peripheral controller, or an intelligent
peripheral that can be attached to the SCSI bus. Small computer interface (SCSI)
IDs are based upon bit-significant representation of the SCSI address that refers
to one of the signal lines (data buses) DB 7-0. In the DEC RAID Subsystem, the
SCSI IDs are assigned on several different levels as shown in Figure 4–1.

SZ200 Base Configuration 4–1

SZ200 Base Configuration
4.1 SCSI IDs for the DEC RAID Subsystem
Figure 4–1 DEC RAID Subsystem SCSI IDs
Host Adapter Connector

Host Adapter Connector

SCSI ID = SW1

Default
SCSI ID = 0

SW1 SW2

HSZ10−AA Controller
J4

J3
Channel Numbers 1

SCSI ID of Disks

J5
4

Channels

1 Disks

SHR−XR3030−GRA

On the host adapter side of the configuration, two connectors provide the SCSI
interconnect to the host system either for local termination or for daisy chaining
to another host.
The HSZ10-AA controller has two switchpacks for setting the SCSI ID of the
controller itself. The HSZ10-AA controller is preset in the factory to the SCSI ID
0 position. The HSZ10-AA Controller Site Preparation Guide describes setting
SW1 to another SCSI ID.
Three connectors on the HSZ10-AA controller (J3, J4, and J5), shown in
Figure 4–1, connect to the five channels of SCSI drive buses. The three
connectors plug directly into the backplane of the shelf.
The position of the HSZ10-AA controller in its slot determines its SCSI ID on
those buses, which can be either SCSI ID 7 or 6. If the controller is in the
BA35X-VA vertical mounting kit, then the left position is SCSI ID 7 and the
right (or middle) position is SCSI ID 6. Refer to Controller 1 and Controller 2 in
Figure 4–2. Controller 1 has a SCSI ID of 7 and Controller 2 has a SCSI ID of 6.
The SCSI ID of the drives is determined by the backplane of the BA350-EA shelf,
and is dependent upon its location in a slot. If the BA35X-EA shelf is in an
upright position (as it is when it is contained in the BA35X-VA vertical mounting
kit), then the bottom slot has a SCSI ID of 0. The top slot has a SCSI ID of 1.
The two slots at the bottom are linked, and 5 and 0 share the connection in the
backplane. Refer to Figure 4–2.

4–2 SZ200 Base Configuration

SZ200 Base Configuration
4.2 HSZ10-AA Controller Location and SCSI Address

4.2 HSZ10-AA Controller Location and SCSI Address
The HSZ10-AA controller must be mounted in the slot marked ‘‘Controller 1’’ in
Figure 4–2. The position of this controller is important since its SCSI ID on the
array channels is set by the backplane. In the slot position, Controller 1, the
controller is set to SCSI ID 7.
A second or redundant controller can be placed in the position marked
‘‘Controller 2.’’
Note
The redundant controller option can only be used by a
host adapter/operating system environment that can accommodate a
redundant controller configuration. Such a configuration is not currently
supported.

Figure 4–2 Physical Drive Map
TO HOST

0
5 T

4 T

3 T

2 T

1 T

5
(6)
0

(6)
POWER

(7) T

POWER
(7)

LEGEND
BACKPLANE CONNECTION

(6) (7)

TERMINATOR

JUMPER
SCSI CABLE
SLOT NUMBERS
SCSI CHANNEL
CXO-3589B-MC

SZ200 Base Configuration 4–3

SZ200 Base Configuration
4.3 Physical Drive Map

4.3 Physical Drive Map
The drive map defines the drives included in the logical unit. Individual drives
are identified by the channel number and SCSI ID. The channel number and
SCSI ID are determined by the physical location of the drive in the array
subsystem. In the BA350-EA shelf, the slot number and SCSI ID are the same
and are used interchangeably.
The following table shows the physical arrangement of the SZ200 base
configuration:
SLOT/SCSI ID
CHANNEL
DRIVE
-------------------------------------0
*
1
5
Drive 1
2
4
Drive 2
3
3
Drive 3
4
2
Drive 4
5
1
Drive 5
SLOT
- Defines the slot position in the BA350-EA shelf
CHANNEL - SCSI bus for the drives on the Array controller
SCSI ID - Drive’s SCSI ID on the Array channel
* NOTE: Reserved for host adapters; for example, the DWZZA-VA.

4.4 Logical Drive Map
The logical mapping of the drives is not the same as the physical arrangement.
The logical map is a grouping of drives. The default configuration is preconfigured
for one logical unit and includes the following five drives:
LOGICAL UNIT
(CHANNEL, SCSI ID)
------------------------------------------------0
(1,5) (2,4) (3,3) (4,3) (5,1)

4.5 DWZZA-VA Bus Adapter
An 8-bit differential SCSI system cannot be connected directly to a single-ended
8-bit SCSI system. However, with the proper adapter, a differential SCSI system
operating in the 8-bit mode is compatible with a single-ended SCSI bus. The
StorageWorks modular storage shelf subsystem uses the DWZZA-VA bus adapter
for compatibility between these two SCSI bus types.
The major features of the DWZZA-VA bus adapter are as follows:
•

No SCSI device modification is required.

•

Supports data transfers at rates up to 10 MBytes per second.

•

Does not use an SCSI device address.

•

It converts two physical buses into one logical bus with a total of eight device
addresses (0 through 7).

•

It can terminate both buses in the end-bus configuration.

•

It can terminate either bus in the midbus configuration.

•

DWZZA-VA operation is transparent to both buses.

4–4 SZ200 Base Configuration

5
Basic Configuration Installation
This chapter discusses installation topics that are specific to the DEC RAID
Subsystem. Since cabinet installation and service instructions are specific to the
cabinet option selected, they are not discussed in this section but can be found in
the StorageWorks documentation set.
For a detailed discussion of the various cable options, refer to Chapter 3 of the
StorageWorks Subsystem Shelf Building Block Configuration Guide.
This chapter discusses the following:
•

Connecting to a host

•

Verifying cables and connectors

•

Powering on the subsystem

•

Functional verification

5.1 Connecting to a Host
The HSZ10-AA controller has a fast, wide, differential host interface. This SCSI-3
interface on the controller is provided through two 68-pin, high-density female
connectors. The specific cable required to connect to the HSZ10-AA controller
(SCSI-3 ‘‘P’’ cable) depends on the type of host/adapter used. Refer to the sections
below for a description of connecting to 16-bit differential, 8-bit differential, and
8-bit single-ended hosts.

5.1.1 Terminating the SCSI Bus
Every SCSI bus must be terminated at both ends to operate reliably. How bus
termination is accomplished with an HSZ10-AA controller depends upon whether
the controller is located at the middle of the bus or at the end of the bus. Refer to
the following list of examples.
•

If an HSZ10-AA controller is located at the end of the bus, terminate the
bus by placing an H879–AA bus terminator (68-pin) on one of the two
HSZ10-AA controller 68-pin connectors. Either connector can contain the
terminator. Connect a SCSI-3 ‘‘P’’ cable to the other HSZ10-AA controller
68-pin connector.

•

If an HSZ10-AA controller occupies a midbus position, attach a SCSI-3 ‘‘P’’
cable to both of the HSZ10-AA controller 68-pin connectors. The bus is then
terminated on whatever device is at the end of the bus.

Basic Configuration Installation 5–1

Basic Configuration Installation
5.1 Connecting to a Host
5.1.2 Connecting to a 16-Bit Differential Host/Adapter
To connect directly to a 16-bit (wide) differential host, a SCSI-3 ‘‘P’’ cable is
needed. The BN21K series cable provides a male, 68-pin, high-density, rightangle connector to the HSZ10-AA controller, and a male, 68-pin, high-density
straight connector to the host. If a right-angle, 68-pin, high-density connection is
required on both ends, then the BN21L series cable should be used.
If the DEC RAID Subsystem is at the end of the bus, a H879-AA bus terminator
is needed. If the DEC RAID Subsystem is in the middle of the bus, use another
SCSI-3 ‘‘P’’ cable to daisy-chain to another device.

5.1.3 Connecting to an 8-Bit Differential Host/Adapter
Connecting to an 8-bit differential host or adapter will vary depending on the
connector and termination on that host or adapter.
In all cases, the SCSI-3 ‘‘P’’ cable will be used on the HSZ10-AA controller. In the
case where the host or adapter uses the SCSI-2 50-pin low-density connector, an
additional ‘‘Y’’ transition cable will be required.
Specifically, connectivity to an EISA-based host system that uses the KZESA
EISA-to-SCSI host adapter requires the following cables. The 68-pin, highdensity, right-angle connector on the BN21K or BN21L cable connects to the
HSZ10-AA controller. The other connector on the HSZ10-AA controller contains
the terminator (H879-AA). The other end of the cable connects to one of the 68pin, female connectors on the the ‘‘Y’’ transition cable (BN21P-0B). This ‘‘Y’’ cable
then connects to the KZESA with the male, 50-pin, low-density straight connector.
An H879-AA terminator connects to the other female, 68-pin, high-density
straight connector, correctly terminating the bus. See Figure 5–1.

Figure 5–1 Typical Y Cable Connection
50-PIN
HIGH-DENSITY OR
LOW-DENSITY
CONNECTOR

68-PIN
HIGH-DENSITY
CONNECTOR
68 CONDUCTOR
CABLE

"Y" CABLE

HSZ SERIES
CONTROLLER

ADAPTER
68-PIN
CONNECTORS
68-PIN
TERMINATOR

68-PIN
DIFFERENTIAL
TERMINATOR
CXO-3587B-MC

5–2 Basic Configuration Installation

Basic Configuration Installation
5.1 Connecting to a Host
5.1.4 Connecting to an 8-Bit Single-Ended Host/Adapter
Connecting the HSZ10-AA controller to an 8-bit, single-ended host or adapter
requires the use of the DWZZA-VA single-ended to differential converter. The
DWZZA-VA is mounted in a standard 3-1/2 inch SBB located in slot 0 of the
StorageWorks shelf.
The DWZZA-VA contains a 68-pin, female differential connector on the front of
the SBB. The connection from the HSZ10-AA controller to the DWZZA-VA is
accomplished using a BN21L cable, which contains a male, 68-pin, right-angle,
high-density connector on each end. The HSZ10-AA must also be terminated
using the H869-AA terminator in the second 68-pin, female connector on the
controller.
The single-ended signals to the DWZZA-VA are provided using a BC09D cable.
This cable has a 50-pin, low-density straight connector for the host connection,
and a 50-pin, high-density straight connector for insertion into the backplane
of the BA350-EA shelf. The section of the BA350-EA shelf that contains the
HSZ10-AA controller also contains a column of 50-pin, high-density connectors on
the right-hand side. The top connector is connected to the DWZZA-VA in slot 0
through the backplane. This is where the high-density connector of the BC09D
cable is inserted. Refer to Figure 5–2.
Figure 5–2 BA350-EA and BA350-SA Combination Storage Array
HOST
BC09D
CABLE

CONTROLLER

CHANNELS

SCSI BUS
INPUT

DWZZA−VA

0
5

BN21L
CABLE

BN21H
CABLE

0
1

5
5
6

BBU
POWER

POWER

AC
DISTRIBUTION

SHR−XR3029−GRA

Basic Configuration Installation 5–3

Basic Configuration Installation
5.1 Connecting to a Host
5.1.5 Maintaining Bus Continuity
A trilink connector block (H885-AA) is available which allows the removal of
devices from the bus without breaking the continuity of the SCSI bus.
The trilink connector block (H885-AA) shown in Figure 5–3 is a small, metal
block with two 68-pin, high-density, female connectors with 2-56 jack standoffs on
one side and a single 68-pin, high-density, male connector with 2-56 jackscrews on
the other side. Using the trilink connector, the HSZ10-AA controller can occupy
either an end-bus or a midbus position, yet remain removable for service.
For midbus connections, follow the steps listed in Table 5–1 and refer to
Figure 5–3.
Table 5–1 Midbus Connections
Step

Procedure

Leave one of the two HSZ10-AA controller connectors open.

Connect the second HSZ10-AA controller connector to the male connector on the
H885–AA trilink connector block.

Attach two BN21L cables to the other side of the trilink connector block.

Figure 5–3 Trilink Connector Midbus Connection
68 CONDUCTOR
CABLE
TRILINK
CONNECTOR
BLOCK
FEMALE

MALE

HSZ SERIES
CONTROLLER

FEMALE

68 CONDUCTOR
CABLE
CXO-3631B-MC

For end-bus connections, follow the steps listed in Table 5–2 and refer to
Figure 5–4.

5–4 Basic Configuration Installation

Basic Configuration Installation
5.1 Connecting to a Host
Table 5–2 End-Bus Connections
Step

Procedure

Leave one of the two HSZ10-AA controller connectors open.

Connect the second HSZ10-AA controller connector to the male connector on the
trilink connector block.

Connect a BN21L cable to one of the female connectors on the trilink block.

Attach the H879–AA terminator to the other female connector on the trilink block.

Figure 5–4 Trilink Connector End-Bus Connection

68 CONDUCTOR
CABLE
TRILINK
CONNECTOR
BLOCK
FEMALE
MALE

HSZ SERIES
CONTROLLER

FEMALE

68-PIN
DIFFERENTIAL
TERMINATOR
CXO-3632B-MC

5.2 Verifying Cables and Connectors
To verify the physical connections, do the following:
•

Ensure that all the cables are securely fastened.

•

Ensure that there are no SCSI ID conflicts with the other devices that are
connected to the same SCSI bus.

•

Ensure that the host SCSI bus is correctly terminated at both ends of the
SCSI bus and is not doubly terminated by other SCSI devices. The bus should
only be terminated at both ends.

•

Ensure that the correct cable and termination scheme, which allows for
different SCSI connection schemes, is followed based on the guidelines set
forth above.

Basic Configuration Installation 5–5

Basic Configuration Installation
5.3 Powering On the Subsystem

5.3 Powering On the Subsystem
To power on the subsystem do the following:
1. Verify that the ac power switch on the ac distribution unit is in the Off
position.
2. Connect the ac input power cable to the ac distribution unit and to the wall
receptacle.
3. Verify that the ac input power cables are inserted firmly into the power
supply SBBs.
4. Turn on the ac power switch and perform functional verification.

5.4 Functional Verification
After powering on the subsystem, you should verify that all the subsystem
components are functioning properly. To do this, perform the following tasks:
1. Verify that both of the LED indicators on all of the power supply SBBs are lit.
2. Verify that all drive SBB activity LEDs initially flash and then go off.
Note
If the drive SBB fault light remains lit, this may not necessarily be a fault
condition. It is important to wait until the unit has been given a start
command from the host and has gone through its initialization process.

3. Verify that all the HSZ10-AA controller LEDs flash on initial power on and
the controller moves to a wait state with binary code 5 and the Heartbeat
LED is beating. For an illustration of the LED indicators, refer to the HSZ10AA Controller Site Preparation Guide. See Section 6.2.2.1 for a description of
the HSZ10-AA controller start-up procedures.

5–6 Basic Configuration Installation

6
Operations
This chapter discusses the following:
•

DEC RAID Subsystem monitoring features

•

User monitoring methods

•

When and how to replace a drive

•

When and how to replace power supplies and blowers

•

Reconstruction

•

Parity/Check Repair

6.1 DEC RAID Subsystem Monitoring Features
The SZ200, once installed and configured, runs with little user intervention. User
intervention is required only if a disk drive fails, if the array configuration needs
to be changed, or if any other subsystem component needs to be replaced.
The DEC RAID Subsystem provides self-monitoring through two components:
•

HSZ10-AA controller

•

StorageWorks shelves (the BA350-EA shelf and/or the BA350-SA shelf)

6.1.1 Monitoring Through the HSZ10-AA Controller
The HSZ10-AA controller monitors drive operation and logical unit status. If
certain errors occur on a drive, the controller changes the status of a drive or
logical unit. A change in drive or logical unit status is a mechanism to alert the
user to the current condition of the array or drives and that maintenance steps
may need to be taken. LUN status is discussed in more detail in Section 6.1.1.1;
drive status is discussed in more detail in Section 6.1.1.2.
In addition, the HSZ10-AA controller is responsible for setting the fault indicators
on the disk drive SBBs. This is done when the controller determines a drive has
failed or the user has actively failed a drive through the DEC RAID utilities.
For more information, refer to the DEC RAID Utilities User’s Guide for the
appropriate operating system.
6.1.1.1 LUN Status
The logical unit or grouping of the drives can be in different states. There are
four possibilities for status, as shown in Figure 6–1.

Operations 6–1

Operations
6.1 DEC RAID Subsystem Monitoring Features
Figure 6–1 LUN State Diagram

> 1 Drive Failure

1 Drive Failure
Degraded

Optimal

Dead

Drive Replacement
Reconstructing

SHR−XR3015−GRA

Table 6–1 describes each logical unit status.
Table 6–1 Logical Unit Status
Status

Description

Optimal

The array is operating at an optimal level. This is the condition during
normal operation.

Degraded

The logical unit is operating in degraded mode. The array is still
functioning, but a single drive could have failed. This state is only
valid for RAID levels that provide redundancy (RAID levels 1, 3, and
5). In order to return the logical unit to optimal, reconstruction of the
data must be done.

Dead

The logical unit is no longer functioning. This is typical when two or
more drives have failed.

Reconstructing

The array controller is currently reconstructing the logical unit using
good data and parity information. This state is valid only for RAID
levels 1, 3, and 5 which provide redundancy.

As detailed in Table 6–1, an optimal status is the desired condition for normal
operation.
If a drive failure does occur in a redundant configuration (RAID 1, 3, or 5) the
DEC RAID Subsystem is operating in a degraded mode. When the array is in
degraded mode, you can still continue to use the array.
In the RAID 1 case, the array controller retrieves the failed drive’s data from its
mirrored drive whenever you read or write to a logical unit in the degraded mode.
In the RAID 3 and 5 case, the array controller determines if the I/O would be
directed to the failed drive as data or parity. For the I/O that must be written
to a data block on the failed drive, the array controller writes the new data to
the operational drives in data blocks. For the I/O that must be written to a data
block on the failed drive, the array controller writes the data to the drives that
contain the data blocks for the I/O, and recalculates the parity for the parity block
of the I/O.
Whenever you issue an I/O that requires the array controller to read from the
failed drive, the array controller recalculates the data and parity blocks from the
data and parity on the operational drives.
If a second drive failure occurs, the array is in a dead state. The data now is no
longer valid. For this reason, it is crucial to replace a drive that has failed right
away before a second drive failure occurs.
6–2 Operations

Operations
6.1 DEC RAID Subsystem Monitoring Features
The process of bringing a degraded LUN back to optimal condition is known
as reconstruction. Reconstruction is a valid state only for redundant RAID
configurations. Data is recreated on the replaced drive using data and parity
from the other drives.
6.1.1.2 Drive Status
Similar to LUN status, drives states are also classified according to status.
Table 6–2 lists the status classifications for drives.
Table 6–2 Drive Status
Status

Description

Optimal

The drive is operating at optimal level.

Warning

The drive has been put into a warning status by the controller as the
result of a read or write error. The severity of this status depends to
some extent on the RAID level of the logical unit. In all cases, the
drive is still usable but should be replaced as soon as possible.

Failed

The drive was failed by the array controller or by using a DEC RAID
utility. The drive must be replaced.

Spare

The drive is connected to an array but not configured into a logical
unit.

Mismatch

The array controller sensed that the drive has different parameters or
configuration information than it expected. This is typical if the user
attempted to replace a drive of different capacity into a logical unit.

An optimal drive state is the desired condition for normal array operation.
A drive is in a warning condition when an error occurs that may require
drive replacement, but does not affect the reliability of the data on the drive.
Conditions that cause the drive to be put into a warning state are as follows:
•

Unrecoverable read errors

•

Read failures due to the drive being powered-off or transient error

A drive in warning state is still used by the controller since it may prove to
be available later. In the case of a read error, the data will be obtained using
redundant information on the other drives. The warning condition provides an
early warning to the user that drive degradation may be occurring. A drive in a
warning state should be replaced with the same urgency as a drive failure.
A drive is marked as failed by the array controller when an error occurs
that leaves the consistency of the user data and redundant information in a
questionable state after using all available recovery actions. When the array
determines that a drive has failed, it will not be used again. Conditions that can
cause a drive to be marked as failed include the following:
•

Unrecoverable errors during a write on a data or redundant information
drive.

•

An error restoring data to a drive after the automatic reallocation of a logical
block.

Operations 6–3

Operations
6.1 DEC RAID Subsystem Monitoring Features
•

Unrecoverable errors during the read portion of a read/modify/write operation
(RAID 5).

•

The user marked a drive as failed using a SCSI command or DEC RAID
utility.

•

An error was reported during disk array format sequence.

6.1.2 Monitoring Through the StorageWorks Shelf
The StorageWorks storage shelves monitor blowers and power. Monitoring is
done by means of a signal in the backplane. Two LED indicators are available
on the power SBBs for status. A fault condition indicates one or more of the
following problems:
•

Power supply failure

•

Blower problem

•

Input power problem

Refer to Section 6.4 for instructions in determining a power supply or blower fault
condition.

6.2 User Monitoring Methods
There are two methods for monitoring the operation of the DEC RAID Subsystem:
•

DEC RAID utilities

•

LED indicators

6.2.1 Monitoring Operation Using the DEC RAID Utilities
The DEC RAID utilities are key tools to maintaining a disk array. They provide
the user with the ability to monitor, configure, repair, and maintain the DEC
RAID Subsystem. Specific utility functionality is dependent on each operating
system since each environment has different needs or capabilities. However,
there are some common concepts and functions that are needed across all
environments. The following is a generic list of functionality available:
•

Check LUN and drive status.

•

Restore the logical unit (RAID levels 1, 3, and 5) after a drive failure.

•

Check and repair array parity on logical units.

•

Configure, reconfigure, and modify logical units.

•

Change default array parameters.

•

Change DEC RAID configuration parameters (scheduled parity time, parity
file name, and so forth).

•

Format a logical array.

•

Download controller software.

•

Check error logs.

A comprehensive description of the DEC RAID utilities is beyond the scope of
this document; therefore, only an overview of operations is provided here. For
more detailed information, refer to the DEC RAID Utilities User’s Guide for the
appropriate operating system.

6–4 Operations

Operations
6.2 User Monitoring Methods
6.2.2 Monitoring Operation Using LED Indicators
The DEC RAID Subsystem also provides visual indicators for maintaining array
operation. The HSZ10-AA controller, shelf, power supply, and disk status can be
monitored using the LEDs.
There are three sets of LED indicators on the subsystem as follows:
•

HSZ10-AA controller LEDs

•

Power supply SBB LEDs

•

Drive SBB LEDs

6.2.2.1 HSZ10-AA Controller LED Indicators
There is a single bank of eight LEDs on the HSZ10-AA controller. These
LEDs convey status information about the boot phase and possible errors. See
Figure 2–2 for the location of the LED display.
Once all the controller diagnostics have passed and the controller is ready to
begin uploading array software from the disk, the Heartbeat LED begins
beating. See Figure 6–2.
Figure 6–2 LED Indicators

Green Power
Light
Flashing
Fault

MSB

LSB

Heartbeat LED
Legend
On
MSB
LSB

Most significant bit
Least significant bit

SHR−XR3022−GRA

The Heartbeat LED, the bottommost LED, beats once per second. During
the upload process, the upper-half of the LEDs displays a binary 5 while the
Heartbeat LED beats rhythmically. After the array software has been uploaded
and is running, the firmware clears the upper LEDs. Thus, as far as the firmware
is concerned, the normal operating mode of any uploaded software has the
Heartbeat LED beating and nothing else.
Table 6–3 shows the LEDs codes displayed by the HSZ10-AA controller. Solid
codes indicate a boot phase and are considered normal conditions. Cyclic or
flashing codes indicate an error condition.

Operations 6–5

Operations
6.2 User Monitoring Methods
Table 6–3 Summary of HSZ10-AA Controller LED Codes
Code
MSB/LSB

S/F/C

State

Description

Solid

None

LEDs are all off, used to flash a value.

Solid

Normal

In between boot phases.

Solid

Normal

Boot scratch pad memory is being tested.

Solid

Normal

ROM is being searched for partitions.

Solid

Normal

ROM partitions are being validated.

Solid

Normal

RAM is being searched for partitions.

Solid

Normal

ROM application partition has been called.

Solid

Debug

Debug mode has been entered.

Solid

Normal

Microprocessor (68020) diagnostics in
progress.

Cyclic

Error

Microprocessor (68020) diagnostics failed.

Solid

Normal

EPROM diagnostics in progress.

Cyclic

Error

EPROM diagnostics failed.

Solid

Normal

EEPROM (58C65) diagnostics in progress.

Cyclic

Error

EEPROM (58C65) diagnostics failed.

Solid

Normal

Processor SRAM diagnostics in progress.

Cyclic

Error

Processor SRAM diagnostics failed.

Solid

Normal

Processor DRAM diagnostics in progress.

Cyclic

Error

Processor DRAM diagnostics failed.

Solid

Normal

Multi-Func Peripheral chip (68901)
diagnostics in progress.

Cyclic

Error

Multi-Func Peripheral chip (68901)
diagnostics failed.

Solid

Normal

Host SCSI channel (53C916) diagnostics in
progress.

Cyclic

Error

Host SCSI channel (53C916) diagnostics
failed.

Solid

Normal

SCSI Data Path chip (53C920) diagnostics in
progress.

Cyclic

Error

SCSI Data Path chip (53C920) diagnostics
failed.

Solid

Normal

Drive SCSI channel (53C96) diagnostics in
progress.

6A 0X

Cyclic

Error

Drive SCSI channel (53C96) diagnostics
failed.

Flashing

Normal

Heartbeat LED.

Solid

Normal

SCSI channel data turnaround diagnostics in
progress.

88 XX

Cyclic

Error

SCSI channel data turnaround diagnostics
failed.
(continued on next page)

6–6 Operations

Operations
6.2 User Monitoring Methods
Table 6–3 (Cont.) Summary of HSZ10-AA Controller LED Codes
Code
MSB/LSB

S/F/C

State

Description

Solid

Normal

Subsystem turnaround diagnostics in
progress.

Cyclic

Error

Subsystem turnaround diagnostics failed.

A0 XX

Cyclic

Error

General fatal error.

F8 XX

Cyclic

Error

General exception error.

F9 XX

Cyclic

Error

Address error.

FA XX

Cyclic

Error

Instruction error.

FB XX

Cyclic

Error

Arithmetic error.

FC XX

Cyclic

Error

Privilege error.

Solid

Normal

Board is in passive mode.

Solid

Normal

Board is held in a hardware reset state failed.

6.2.2.2 Power Supply LEDs
Shelf and power supply status are displayed on the power supply LEDs shown in
Figure 6–3. The upper LED displays the status of the shelf and the lower LED
displays the status of the supply.
Figure 6–3 Power Supply Status LEDs

SHELF
STATUS LED

POWER SUPPLY
STATUS LED

CXO-3613B-PH

•

When the upper LED is on, both the blowers and the power supplies are
functioning properly.

•

When the upper LED is off, one of these fault conditions exists.

Operations 6–7

Operations
6.2 User Monitoring Methods
For a detailed explanation of the power supply LED codes, refer to Tables 6–4
and 6–5.
Table 6–4 Shelf and Single Power Supply Status LEDs
Status LED

Status

Indication

Shelf (upper)
PS (lower)

On
On

NORMAL Status
System is operating normally.
There are no shelf or power supply faults.

Shelf (upper)
PS (lower)

Off
On

FAULT Status
There is a shelf fault; there is no power supply fault.
Replace the blower.

Shelf (upper)
PS (lower)

Off
Off

FAULT Status
Shelf and power supply fault. Refer to Section 6.4.

Table 6–5 Shelf and Dual Power Supply Status LEDs
Status LED

PS1

PS2

Indication

Shelf (upper)
PS (lower)

On
On

NORMAL Status
System is operating normally.
There are no shelf or power supply faults.

Shelf (upper)
PS (lower)

Off
On

FAULT Status
There is a shelf fault.
There is no power supply fault.
Replace the blower.

Shelf (upper)
PS (lower)

Off
On

Off
Off

FAULT Status
PS1 operational.
Replace PS2.

Shelf fault
PS (lower)

Off
Off

Off
On

FAULT Status
PS2 operational.
Replace PS1.

Shelf (upper)
PS (lower)

Off
Off

FAULT Status
Possible PS1 and PS2 fault or possible input power
problem.

6.2.2.3 Drive SBB LEDs
Each drive SBB has two LED indicators, as shown in Figure 6–4, which display
the SBB’s status. These LEDs have three states as follows:

6–8 Operations

•

Off

•

Flashing

Operations
6.2 User Monitoring Methods
Figure 6–4 Shelf Status LEDs

CXO-3614A-PH

•

The top left LED (green) is the device activity LED and is on or flashing when
the SBB is active.

•

The bottom LED (amber) is the drive SBB fault LED and defines the error
condition, as indicated by the state of the LED – either on or flashing.
Note
On initial power-on of the DEC RAID Subsystem, the bottom LED
(amber) may be lit. This does not indicate a fault condition. A bus
reset is required from the host to clear these lights.

Table 6–6 Drive SBB Status LEDs
LED

Status

Indication

SBB activity
SBB fault

On
Off

SBB is operating normally.

SBB activity
SBB fault

On
On

Fault state. SBB is probably hung up. It is
recommended that you replace the SBB.

SBB activity
SBB fault

Off
On

Fault state. SBB is inactive and spun down. It
is recommended that you replace the SBB.

SBB activity
SBB fault

On
Flashing

Fault state. SBB is active and drive is being
spun down because of fault.

If a fault state exists, refer to Section 6.3 for instructions in replacing a drive
SBB.

Operations 6–9

Operations
6.3 When and How to Replace a Drive

6.3 When and How to Replace a Drive
You need to replace a drive when the following occurs:
•

DEC RAID utilities provide information stating that a drive is in a warning
state.

•

DEC RAID utilities provide information stating that a drive is in a failed
state.

•

Drive SBB fault indicator is on.

The HSZ10-AA controller and StorageWorks products allow for hot swapping a
drive SBB. This means the user can remove and replace a drive SBB without
interrupting host operation or removing power to the subsystem.
The following are steps you should take to replace a drive:
1. If the drive is not yet in a failed state, fail the drive using the DEC RAID
utilities.
2. Wait until the right LED (amber) light is solid (the flashing has stopped).
3. Press the two mounting tabs to release the unit, and slide the unit out of the
shelf, as shown in Figure 6–5.
Figure 6–5 Replacing a Drive

CXO-3611B-PH

4. Wait 10 seconds before inserting a new drive SBB.
5. Insert the replacement drive unit into the guide slots and push it in until the
tabs lock into place.
6. Wait for the HSZ10-AA controller to spin up the new drive.
7. Perform the reconstruction process, if needed. Refer to Section 6.5 for more
detailed information.

6–10 Operations

Operations
6.3 When and How to Replace a Drive
Note
It is important that you wait at least 10 seconds before inserting a new
drive SBB. The HSZ10-AA controller requires this period to scan the SCSI
buses and to become informed of a drive removal.

6.4 When and How to Replace Power Supplies and Blowers
You need to replace a power supply or blower when the LEDs indicate a fault
condition as outlined in Section 6.2.2.2.
The input power for each ac power supply is controlled by a switch on the
cabinet power controller. Turning this switch off removes power from all power
supplies in the cabinet. To remove power from a single power supply, you simply
disconnect the power cable from that power supply.
There are three swapping methods for replacing power supplies as follows:
•

Hot swapping—The hot swapping method is used when there are two power
supplies in a shelf. This method allows you to remove the defective power
supply while the other power supply furnishes the power.

•

Warm swapping—The warm swapping method is used when there is
no operational power supply, but all the other shelf power supplies in a
cabinet are functioning properly. In this case, none of the shelf devices are
operational until the replacement power supply is installed.
Note
Whenever operational requirements permit, it is recommended that you
use the warm swapping method.

•

Cold swapping—The cold swapping method is used when the input power
is removed from all shelves in a cabinet. This normally only occurs during
initial installation. None of the shelves are operational until the input power
is restored.

6.4.1 Replacing a Shelf Power Supply
Warning
Always use both hands when removing or replacing an SBB, to fully
support its weight.

To replace either a shelf primary or redundant power supply, complete the
following procedure:

Operations 6–11

Operations
6.4 When and How to Replace Power Supplies and Blowers
Step

Procedure

Remove the input power cable from the power supply.

Press the two mounting tabs to release the unit, and slide the unit out of the shelf.
This is similar to replacing a drive as shown in Figure 6–5.

Insert the replacement unit into the guide slots and push it in until the tabs lock
into place.

Connect the input power cord.

Observe the LEDs and ensure the power supply is functioning properly (refer to
Table 6–4 or to Table 6–5).

Note: Use this step only when you have a single power supply. Sequentially
place the storage devices online. Observe the LEDs on both the power supply and
the storage device for normal operation indications.

6.4.2 Replacing a Blower
Each shelf has two blowers mounted on the rear. Connectors on the backplane
provide the +12 Vdc to operate the blowers. As long as one blower is operational
on each shelf, there is sufficient airflow to prevent an overtemperature condition.
When either blower fails, the upper (shelf status) LED on the power SBB turns
on.
Warning
Service procedures described in this manual involving blower removal or
access to the rear of the shelf must be performed only by qualified service
personnel.
To reduce the risk of electrical energy hazard, disconnect the power cables
from the shelf power SBBs before removing shelf blower assemblies or
performing service in the backplane area, such as modifying the SCSI
bus.

When a blower is removed, the change in the airflow pattern reduces the cooling
to the point that the shelf can overheat within 60 seconds.
Note
Replacing a blower requires access to the rear of the shelf.
When you cannot access the rear of the shelf you must turn off the power,
remove the shelf from the cabinet, and perform steps 1 through 6 listed in
Table 6–7.
Then replace the shelf in the cabinet and apply power.

To replace a blower, follow the steps in Table 6–7:

6–12 Operations

Operations
6.4 When and How to Replace Power Supplies and Blowers
Table 6–7 Blower Replacement
Step

Procedure

Disconnect all power cables to shelf power SBBs.

Use a Phillips screwdriver to remove the safety screw in the upper right corner of
the blower.

As shown in Figure 6–6, press the upper and lower blower mounting tabs in to
release the blower.

Pull the blower straight out to disconnect it from the shelf power connector.

Align the replacement blower connector and insert the module, straight in, making
sure that both mounting tabs are firmly seated in the shelf.

Replace the safety screw in the upper right corner of the blower.

Connect the shelf power cables and verify that the shelf and all SBBs are operating
properly.

Figure 6–6 Replacing BA35X–MA Blowers

CXO-3515A-PH

6.5 Reconstruction
By default, the HSZ10-AA controller automatically initiates the reconstruction
process after you replace a drive in a degraded RAID 1 or 5 logical unit. Through
the DEC RAID utilities, you may change the default configuration and schedule
reconstruction or manually start reconstruction on the replaced drive.
Reconstruction is a process used to restore a degraded RAID 1 or 5 logical unit to
its original state after a single drive has been replaced. During reconstruction,
the HSZ10-AA controller recalculates the data on the drive that was replaced,
using data and parity from the other drives in the logical unit. The controller
then writes this data to the replaced drive. Note that although RAID level 1 does
not have parity, the array controller can reconstruct data on a RAID 1 logical unit
by copying data from the mirrored disk.

Operations 6–13

Operations
6.5 Reconstruction
Note
Reconstruction applies only to a degraded RAID 1 or 5 logical unit with a
single-drive failure.

Once reconstruction is initiated (either by you or by the array controller), the
HSZ10-AA controller completes the following actions:
•

Formats the new drive (if the array controller determines it is necessary).

•

Copies special array software files to the new drive.

•

Recalculates the data and parity from the data and parity on the other logical
unit drives.

•

Writes the recalculated data and parity to the new drive.

Once reconstruction is started, it can take place while the logical unit is in use.
You do not need to shut down the DEC RAID Subsystem. You can see the access
to all the drives in the logical unit for a period of time. The length of time it
takes for reconstruction to complete depends upon the drive capacity and the
reconstruction settings.
Important
Do not remove a second drive during the reconstruction process. Doing so
may result in data loss.

6.6 Parity Check/Repair
It is important for the user to perform periodic parity checks on the redundant
arrays, especially if there is a power failure or an abnormal shutdown.
Parity Check/Repair is the process of verifying and repairing parity information
so that data can be maintained and reconstructed if there is a drive failure.
Parity Check/Repair functionality is provided by the DEC RAID utilities.
Note
Parity Check/Repair applies only to RAID 1 and 5. RAID 0 does not have
array parity, and therefore cannot be checked and repaired. RAID 1 does
not actually have parity either, but parity check compares data on the
mirrored drives. Parity Check/Repair cannot be performed on a degraded
logical unit.

Parity Check/Repair performs the following functions:
•

Scans the logical unit and checks the array parity for each block in the logical
unit. On a RAID 1 logical unit, Parity Check compares the data on each
mirrored pair of disks, block by block.

•

Repairs any array parity errors found during the parity check.

6–14 Operations

Operations
6.6 Parity Check/Repair
Note that if the array parity errors resulted from corrupted data, the data is
not repaired, only the array parity. Also, note that you may still lose some
data as a result of the power failure or abnormal shutdown, especially if you
do not have an uninterruptible power supply (UPS). Data cached in buffers
will be lost and cannot be reconstructed if you do not have a UPS. This is
one of the reasons you should always maintain backup files, even with a
redundant array.
DEC RAID Parity Check/Repair utility can be run at the following times:
•

Automatic parity check/repair will guarantee the data integrity of the logical
unit so that you can reconstruct the data on the array if a drive fails. This
procedure is either set at a time determined during the installation of the
DEC RAID Utility, or it can be set up by means of a script that runs at a set
time.

•

Manually after an abnormal server or array shutdown. As the result of such
a shutdown, required array parity may not have been updated, resulting in
potential data corruption.

For more detailed information, refer to the DEC RAID Utilities User’s Guide for
the appropriate operating system

6.7 Upgrading Software
The disk array software can be upgraded using a DEC RAID utility, which
provides downloading capability. Upgrading the software does not affect the user
data.
Refer to the DEC RAID Utilities User’s Guide for instruction regarding upgrading
the software.

Operations 6–15

7
Advanced Configurations
To do advanced configurations, you need to use one of the RAID Manager
utilities. The following sections outline the configuration limits and steps needed
for reconfigurations. All information is given in a generic sense, and specific
details are described in the DEC RAID Utilities User’s Guide for the appropriate
operating system.
This chapter discusses the following:
•

Modifying basic configurations

•

Multiple rank configurations

•

Configuration guidelines

•

Recommended configurations

•

Custom expansions

7.1 Modifying Basic Configurations
If the preconfigured base subsystem does not meet your needs, you can do one or
more of the following:
•

Modify the RAID level.

•

Modify the Drive Mapping and Logical Unit configurations.

•

Modify the parameter characteristics such as segment size and reconstruction
frequency.

Some restrictions exist with drive selection on different RAID levels:
RAID Level

Drive Map Restrictions

Number of drives allowed per logical unit = 1 to 5.

Number of drives allowed per logical unit = 2 to 4.
Must specify an even number of drives.
The mirrored pair is created by grouping the first and second drive you
enter, third and fourth, and so on.
Drives on mirrored pair cannot be on the same channel.

Supports 3 or 5 drives.

Number of drives allowed per logical unit = 3 to 5.
Each drive must be on separate channel.

ALL

Drives within a RAID level must be of same vendor type and capacity.

Advanced Configurations 7–1

Advanced Configurations
7.1 Modifying Basic Configurations
Note
It is recommended that you use the maximum number of drives when you
create a logical unit.

7.2 Multiple Rank Configurations
The DEC RAID Subsystem can be expanded up to seven ranks. This means
it can support up to 7 disks per channel or a total of 35 drives. Expansion is
done by adding StorageWorks BA350-SA shelves to the base BA350-EA shelf. In
addition, RAID level types can be mixed within a configuration. For example,
a 4-rank configuration can be built in which two of the ranks are RAID level 5
configurations and the other two ranks are RAID level 0 configurations. Both the
expansion and configuration flexibility allow the user to create new configurations
that meet their growing business needs.
Certain expansion paths may require reconfiguration of your array and rebuilding
of your data. This is because, with certain expansion paths, you cannot maintain
the same array channel and SCSI ID for drives when you migrate from one shelf
to multiple shelves. The array channel and SCSI ID information is critical for
maintaining the integrity of your array.
Before planning to expand your configuration, review Section 7.3 to understand
the RAID configuration and expansion path restrictions.

7.3 Configuration Guidelines
A key feature of the DEC RAID Subsystem is that it provides the capability
of mixing different RAID level types. However, there are some guidelines and
restrictions you must follow when configuring multiple rank systems.
These restrictions are listed below:
RAID Level

Drive Map Restrictions

Number of drives allowed per logical unit = 1 to 10.

Number of drives allowed per logical unit = 2 to 10.
Must specify an even number of drives.
The mirrored pair is created by grouping the first and second drive you
enter, third and fourth, and so on.
Drives on mirrored pair cannot be on the same channel.

Number of drives allowed per logical unit = 3 to 5.
Each drive must be on separate channel.

ALL

Drives within a RAID level must be of same vendor type and capacity.

Recommendations
It is recommended that you configure a logical unit with the maximum
number of drives (for example, five drives) to prevent performance issues.
It is recommended, with multiple-rank configurations, that disk drives
that support the SCSI-3 messages Target Transfer Disable (TTD) and
Continue I/O Process (CIOP) are used. This gives the array controller

7–2 Advanced Configurations

Advanced Configurations
7.3 Configuration Guidelines
the ability to sequence data transfers across a bus with multiple targets
present.

The following are examples of legal and illegal configurations.
LEGAL: Since all LUNs are unique RAID levels.
LOGICAL UNIT
(CHANNEL, SCSI ID)
RAID LEVEL
------------------------------------------------------------0
(1,1) (2,1) (3,1) (4,1) (5,1)
5
1
(1,2) (2,2) (3,2) (4,2)
0
2
(1,3) (2,3) (3,3) (4,3) (5,2)
1
3
(1,4) (2,4) (3,4) (4,4) (5,4)
5
ILLEGAL: Since attempting to mix RAID level 5 and 0 within
logical unit 0.
LOGICAL UNIT
(CHANNEL, SCSI ID)
RAID LEVEL
------------------------------------------------------------0
(1,1) (2,1) (3,1) (4,1) (5,1)
5,0
1
(1,2) (2,2) (3,2) (4,2)
0
2
(1,3) (2,3) (3,3) (4,3) (5,2)
1
3
(1,4) (2,4) (3,4) (4,4) (5,4)
5

7.3.1 Expansion Guidelines
There are three recommended packaging expansion paths as follows:
•

Single BA350-EA to Single BA350-EA/Dual BA350-SA
Allows expansion from 1 rank to a maximum of 3 ranks of drives.

•

Single BA350-EA to Single BA350-EA/Quad BA350-SA
Allows expansion from 1 rank to a maximum of 6 ranks of drives.

•

Single BA350-EA/Dual BA350-SA to Single BA350-EA/Quad BA350-SA
Allows expansion from 4 ranks to a maximum of 6 ranks of drives.

These paths are recommended because they do not require reconfiguration of
your array. For each path, information is provided on the steps required for the
expansion. Each of the sections provides the following:
•

Shelf requirements

•

Instructions

•

A shelf reconfiguration diagram

•

A drive reconfiguration diagram

The shelf reconfiguration diagram is to be used for cable, terminator, and jumper
reconfiguration. The drive reconfiguration diagram is to be used for drive
movement and recommended rank drive mapping.
Recommendation
It is strongly recommended that you select a path that does not require
rebuilding of data.

Advanced Configurations 7–3

Advanced Configurations
7.3 Configuration Guidelines
Refer to Table 7–1 for a listing of the possible expansion paths available to you.
Table 7–1 Expansion Paths

Present

Future

BA350-EA

BA350-SA

Custom
Reconfiguration
Needed

1 Rank

2 Ranks

Yes

Section 7.5

1 Rank

2 Ranks

Section 7.4.1

Refer to:

1 Rank

3 Ranks

Section 7.4.1

1 Rank

4 Ranks

Section 7.4.2

1 Rank

5 Ranks

Section 7.4.2

1 Rank

6 Ranks

Section 7.4.2

2 Ranks

3 Ranks

Yes

Section 7.5

2 Ranks

4 Ranks

Section 7.4.3

2 Ranks

5 Ranks

Section 7.4.3

2 Ranks

6 Ranks

Section 7.4.3

3 Ranks

4 Ranks

Section 7.4.3

3 Ranks

5 Ranks

Section 7.4.3

3 Ranks

6 Ranks

Section 7.4.3

4 Ranks

5 Ranks

Section 7.4.3

4 Ranks

6 Ranks

Section 7.4.3

5 Ranks

6 Ranks

Section 7.4.3

7.4 Recommended Configurations
The following sections describe the recommended expansion paths. Each section
describes the following:
•

Shelf requirements

•

Purpose of the expansion

•

Pre-reconfiguration tasks

•

Reconfiguration tasks

•

Post-reconfiguration tasks

7–4 Advanced Configurations

Advanced Configurations
7.4 Recommended Configurations
7.4.1 Expansion from a Single BA350-EA to a Single BA350-EA/Dual
BA350-SA Configuration
This section describes how to expand your one BA350-EA shelf configuration with
two BA350-SA shelves, expanding to a maximum of three ranks of drives. Each
rank contains five drives.

Shelf Requirements: One BA350-EA shelf, Two BA350-SA shelves
This expansion allows you to expand to either two ranks of drives (10 drives) or
three ranks of drives (15 drives).

Purpose
The single BA350-EA configuration contains one rank of drives (5 drives, 1 per
channel). In expanding to a second rank, an additional five drives are added to
the configuration (ten drives, two drives per channel). In expanding to a third
rank, an additional ten drives are added to the configuration (fifteen drives, three
drives per channel). This expansion path requires cabling two additional BA350SA shelves, and relocating the initial five drives into slots at the same channel
and SCSI IDs as in the original configuration.
To expand your configuration, perform the following sets of tasks:
•

Pre-reconfiguration

•

Shelf reconfiguration

•

Post-reconfiguration

7.4.1.1 Pre-Reconfiguration
Before you begin to expand your configuration, perform the following steps:
1. Back up your data to other media.
2. Figure 7–1 shows your current configuration. Use Figure 7–1 as the guide
for identification information. Label each of your current drives with array
channel and SCSI ID information.

Advanced Configurations 7–5

Advanced Configurations
7.4 Recommended Configurations
Figure 7–1 Single BA350-EA Shelf
TO HOST

0
5 T

4 T

3 T

2 T

1 T

5
(6)
0

(6)
POWER

(7) T

POWER
(7)

LEGEND
BACKPLANE CONNECTION
T

TERMINATOR

JUMPER

(6) (7)

SCSI CABLE
SLOT NUMBERS
SCSI CHANNEL
CXO-3589B-MC

Note
You can label the SBB in pencil. You can erase the SBB later and relabel
it as needed.

3. Figure 7–2 shows the physical layout of the reconfiguration. Figure 7–3
represents the logical view of the reconfiguration. Study Figure 7–2 and
Figure 7–3 to be certain that you understand the cabling and relocation of
drives. Refer to Chapter 5 to review connection information.
4. Power down the DEC RAID Subsystem.
You are ready to begin the shelf reconfiguration described in Section 7.4.1.2.
7.4.1.2 Shelf Reconfiguration
To expand your configuration, perform the following steps:
1. Reconfigure your BA350-EA shelf and BA350-SA shelves using the diagram
shown in Figure 7–2.

7–6 Advanced Configurations

Advanced Configurations
7.4 Recommended Configurations
Figure 7–2 Single BA350-EA to Single BA350-EA/Dual BA350-SA Shelf
Reconfiguration

0
5 T

4 J

3 J

2 T

1 J

5
0
(6)

(6)
POWER (7) T

JA1

JB1

POWER
(7)

JA1

JB1

0
J

0
J
1

T
5

POWER (7)

SHELF 1

SHELF 2
CXO-3650B-MC

To begin, the BA350-EA shelf is reconfigured by removing some of the
terminators and adding jumpers instead. The jumpers and terminators
are located at the back of the unit on the backplane.
•

Add the jumpers at SCSI ID slots 2 and 3. This connects those SCSI IDs
to channel 5.

•

Add the jumper at SCSI ID slot 5. This connects SCSI IDs 4, 5, and 0
to channel 2. Note that SCSI IDs 5 and 0 are connected through the
backplane and no jumper is required.

Advanced Configurations 7–7

Advanced Configurations
7.4 Recommended Configurations
Refer to Figure 7–3. The channel and SCSI ID are designated as (x,y) or
(channel, SCSI ID). For example, channel 5, SCSI ID 1 is designated as (5,1).
The BA350-EA shelf now has channel and SCSI IDs (5,1), (5,2), (5,3), (2,4),
(2,5), (2,0). The jumpers at SCSI ID slots 2, 3, and 5 have freed up channels
4, 3, and 1 to be routed to the BA350-SA expansion shelves.
The BA350-SA expansion shelves contain eight slots and can hold up to seven
drives. Starting at the top of the shelf, the SCSI IDs are 0 to 6. The BA350SA shelf can be configured as either one SCSI bus with IDs 0 through 6, or as
two separate SCSI buses with the following IDs on each bus:
•

SCSI IDs 1, 3, 5, and 6

•

SCSI IDs 0, 2, and 4

If a terminator is placed in slot 5 (SCSI ID 5), then the SCSI buses will be
separate. Otherwise, if you put a jumper in slot 5, then the SCSI IDs are all
connected together.
1. For purposes of this configuration, put a terminator in slot 5 as shown in
Figure 7–2. As you continue with the reconfiguration, be certain to follow
the pattern of jumpers and terminators shown in Figure 7–2.
2. Using Figure 7–3 as a guide, perform the following steps:
Figure 7–3 Single BA350-EA to Single BA350-EA/Dual BA350-SA Drive
Reconfiguration
350−E

350−E

350−S

ADD 0

(5,1) 1
(4,2) 2

(5,1) 1

ADD 1

ADD 2

(4,2) 2

(3,3) 3

ADD 3
(2,4) 4

(3,3) 3

ADD 5

ADD 3
ADD 4
(1,5) 5

ADD 0

(2,4) 4
(1,5) 5
0

4
ADD 5

Rank 1: (5,1) (4,2) (3,3) (2,4) (1,5)
Rank 2: (5,2) (4,4) (3,5) (2,5) (1,3)
Rank 3: (5,3) (4,0) (3,1) (2,0) (1,1)
(x,y) = (Channel, SCSI Id)
SHR−XR3016−GRA

a. Connect the BA350-SA shelves to the BA350-EA shelf.
The section of the BA350-EA shelf that contains the HSZ10-AA
controller contains a column of six 50-pin, high-density connectors
on the right-hand side. These connectors are labeled as channels
in Figure 7–4. The top connector is used exclusively for connecting
to host adapter SSBs (for example, the DWZZA-VA) in slot 0 and
that connector is unnumbered in Figure 7–4. The other connectors
are labeled as 5, 4, 3, 2, and 1.

7–8 Advanced Configurations

Advanced Configurations
7.4 Recommended Configurations
The BA350-SA shelf contains two 50-pin, high-density connectors
on the backplane at the top of the shelf. If you look at the shelf
from the front, the left-hand connector connects SCSI IDs 0, 2,
and 4. The right-hand connector connects SCSI IDs 1, 3, and 5.
As previously discussed, these SCSI buses are independent of each
other unless you put a jumper in slot 5.
To connect a channel to the BA350-SA shelf, run a cable from
the BA350-EA shelf to the BA350-SA shelf. Use a BN21H
Series cable, which has two 50-pin, high-density, male, straight
connectors.
b. For this configuration, connect channels 1, 3, and 4 from the BA350EA shelf to the BA350-SA shelves as follows:
Attach a BN21H cable from channel 1 of the BA350-EA shelf to
the right-hand connector in the BA350-SA shelf. This connects
channel 1 with the SCSI IDs 1, 3, and 5, as shown in Figure 7–4.
Figure 7–4 BA350-EA and BA350-SA Combination Storage Array
HOST
BC09D
CABLE

CONTROLLER

CHANNELS

SCSI BUS
INPUT

DWZZA−VA

0
5

BN21L
CABLE

BN21H
CABLE

0
1

5
5
6

BBU
POWER

POWER

AC
DISTRIBUTION

SHR−XR3029−GRA

Attach a cable in channel 4 of the BA350-EA shelf to the left-hand
connector in the BA350-SA shelf. This connects channel 4 to SCSI
IDs 0, 2, and 4.

Advanced Configurations 7–9

Advanced Configurations
7.4 Recommended Configurations
Connect channel 3 to the second BA350-SA shelf by attaching
a cable to channel 3 in the BA350-EA shelf to the right-hand
connector of the second BA350-SA shelf (SCSI IDs 1, 3, and 5).
Refer to Figure 7–2.
c.

At this point, the original five drives from the BA350-EA shelf must
be inserted in locations with the same channel and SCSI ID as
originally assigned to the drive. This will allow the operating system
to recognize the original LUNs immediately. The original channel and
SCSI ID assignments were (5,1), (4,2), (3,3), (2,4), and (1,5).
In the new configuration, drives (5,1) and (2,4) are still in the
BA350-EA shelf, while drives (4,2), (3,3), and (1,5) must be relocated
to the BA350-SA shelves. Refer to Figure 7–3.

3. To expand to two ranks, add an additional five drives in the slot locations
designated by the rank-2 list.
These drives must be inserted in the following locations: (5,2) and (2,5) in
the BA350-EA shelf, and (4,4), (3,5), and (1,3) in the BA350-SA shelves.
Refer to Figure 7–3.
4. To expand to three ranks, add an additional five drives in the slot
locations designated by the rank-3 list.
These drives must be inserted in the following locations: (5,3) and (2,0) in
the BA350-EA shelf, and (4,0), (3,1), and (1,1) in the BA350-SA shelves.
Refer to Figure 7–3.
2. Power on the DEC RAID Subsystem.
You have completed the shelf reconfiguration. Verify that you have correctly
reconfigured your BA350-EA with two BA350-SA shelves as described in
Section 7.4.1.3.
7.4.1.3 Post-Reconfiguration
To verify your configuration, use DEC RAID Utilities appropriate for your
operating system to perform the following steps:
1. Verify that original drives are all set to optimal condition.
2. Verify that new drives are displayed as ‘‘spare’’ drives in the proper
array channel/SCSI ID positions.
3. Configure and format desired RAID level configurations.
4. Reboot the system.

7–10 Advanced Configurations

Advanced Configurations
7.4 Recommended Configurations
7.4.2 Expansion from a Single BA350-EA to a Single BA350-EA/Quad
BA350-SA Configuration
This section describes how to expand your one BA350-EA shelf configuration with
four BA350-SA shelves, expanding to a maximum of six ranks of drives. Each
rank contains five drives.

Shelf Requirements: One BA350-EA shelf, Four BA350-SA shelves
This expansion allows you to expand from two ranks of drives (10 drives) to up to
six ranks of drives (30 drives).

Purpose
The single BA350-EA configuration contains one rank of drives (5 drives, 1
per channel). Expansion involves adding additional ranks of five drives to the
configuration. This expansion path requires cabling four additional BA350-SA
shelves, and relocating the initial five drives into slots at the same channel and
SCSI IDs as in the original configuration.
To expand your configuration, perform the following sets of tasks:
•

Pre-reconfiguration

•

Shelf reconfiguration

•

Post-reconfiguration

7.4.2.1 Pre-Reconfiguration
Before you begin to expand your configuration, perform the following steps:
1. Back up your data to other media.
2. Figure 7–5 shows your current configuration. Use Figure 7–5 as the guide
for identification information. Label each of your current drives with array
channel and SCSI ID information.

Advanced Configurations 7–11

Advanced Configurations
7.4 Recommended Configurations
Figure 7–5 Single BA350-EA Shelf
TO HOST

0
5 T

4 T

3 T

2 T

1 T

5
(6)
0

(6)
POWER

(7) T

POWER
(7)

LEGEND
BACKPLANE CONNECTION

(6) (7)

TERMINATOR

JUMPER
SCSI CABLE
SLOT NUMBERS
SCSI CHANNEL
CXO-3589B-MC

Note
You can label the SBB in pencil. You can erase the SBB later and relabel
it as needed.

3. Figure 7–6 shows the physical layout of the reconfiguration. Figure 7–7
represents the logical view of the reconfiguration. Study Figure 7–6 and
Figure 7–7 to be certain that you understand the cabling and relocation of
drives. Refer to Chapter 5 to review connection information.
4. Power down the DEC RAID Subsystem.
You are ready to begin the shelf reconfiguration described in Section 7.4.2.2.
7.4.2.2 Shelf Reconfiguration
To expand your configuration, perform the following steps:
1. Reconfigure your BA350-EA shelf and BA350-SA shelves using the diagram
shown in Figure 7–6.

7–12 Advanced Configurations

Advanced Configurations
7.4 Recommended Configurations
Figure 7–6 Single BA350-EA to Single BA350-EA/Quad BA350-SA Shelf
Reconfiguration

0
5 T
4
3
2
1

J
2
J
3
J
4
J
5
(6)
0

(6)
POWER
POWER (7) T

JA1

JB1

JA1

JB1

0
T

JA1

JB1

0
T

JA1

JB1

0
T

4
J

(7)

4
J

POWER (7)

SHELF 1

SHELF 2

SHELF 3

SHELF 4
CXO-3594B-MC

To begin, the BA350-EA shelf is reconfigured by removing some of the
terminators and adding jumpers instead. The jumpers and terminators
are located at the back of the unit on the backplane.
•

Add the jumpers at SCSI ID slots 2, 3, 4, and 5. This connects SCSI IDs
1, 2, 3, 4, 5, and 0 to channel 5. Note that SCSI IDs 5 and 0 are connected
through the backplane and no jumper is required.

Refer to Figure 7–7. The channel and SCSI ID are designated as (x,y) or
(channel, SCSI ID). For example, channel 5, SCSI ID 1 is designated as (5,1).

Advanced Configurations 7–13

Advanced Configurations
7.4 Recommended Configurations
The BA350-EA shelf now has channel and SCSI IDs (5,1), (5,2), (5,3), (5,4),
(5,5), (5,0). The jumpers at SCSI ID slots 2, 3, 4, and 5 have freed up channels
4, 3, 2, and 1 to be routed to the BA350-SA expansion shelves.
The BA350-SA expansion shelves contain eight slots and can hold up to seven
drives. Starting at the top of the shelf, the SCSI IDs are 0 to 6. The BA350SA shelf can be configured as either one SCSI bus with IDs 0 through 6, or as
two separate SCSI buses with the following IDs on each bus:
•

SCSI IDs 1, 3, 5, and 6

•

SCSI IDs 0, 2, and 4

If a terminator is placed in slot 5 (SCSI ID 5), then the SCSI buses will be
separate. Otherwise, if you put a jumper in slot 5, then the SCSI IDs are all
connected together.
1. For purposes of this configuration, put a terminator in slot 5 as shown in
Figure 7–6. As you continue with the reconfiguration, be certain to follow
the pattern of jumpers and terminators shown in Figure 7–6.
2. Using Figure 7–7 as a guide, perform the following steps:
Figure 7–7 Single BA350-EA to Single BA350-EA/Quad BA350-SA Drive
Reconfiguration
350−E

350−E

350−S

ADD 1
ADD 2
(3,3) 3

ADD 1
ADD 2

ADD 3
(2,4) 4

ADD 3
ADD 4
(1,5) 5

(4,2) 2

(5,1) 1
ADD 2

(3,3) 3

ADD 3

ADD 1
(4,2) 2
ADD 3

(2,4) 4

ADD 4

(1,5) 5

ADD 5

(5,1) 1

350−S

ADD 5
6

Rank 1: (5,1) (4,2) (3,3) (2,4) (1,5)
Rank 2: (5,2) (4,1) (3,1) (2,1) (1,2)
Rank 3: (5,3) (4,3) (3,2) (2,2) (1,3)
Rank 4: (5,4) (4,4) (3,4) (2,3) (1,4)
Rank 5: (5,5) (4,5) (3,5) (2,4) (1,1)
Rank 6: (5,0) (4,0) (3,0) (2,0) (1,0)
(x,y) = (Channel, SCSI Id)
SHR−XR3017−GRA

a. Connect the BA350-SA shelves to the BA350-EA shelf.
The section of the BA350-EA shelf that contains the HSZ10-AA
controller contains a column of six 50-pin, high-density connectors
on the right-hand side. These connectors are labeled as channels
in Figure 7–5. The top connector is used exclusively for connecting
to host adapter SSBs (for example, the DWZZA-VA) in slot 0, and
that connector is unnumbered in Figure 7–5. The other connectors
are labeled as 5, 4, 3, 2, and 1.

7–14 Advanced Configurations

Advanced Configurations
7.4 Recommended Configurations
The BA350-SA shelf contains two 50-pin, high-density connectors
on the backplane at the top of the shelf. If you look at the shelf
from the front, the left-hand connector connects SCSI IDs 0, 2,
and 4. The right-hand connector connects SCSI IDs 1, 3, and 5.
As previously discussed, these SCSI buses are independent of each
other unless you put a jumper in slot 5.
To connect a channel to the BA350-SA shelf, run a cable from
the BA350-EA shelf to the BA350-SA shelf. Use a BN21H
Series cable, which has two 50-pin, high-density, male, straight
connectors.
b. For this configuration, connect channels 1, 2, 3, and 4 from the
BA350-EA shelf to the BA350-SA shelves as follows:
Attach a BN21H cable from the channel in the BA350-EA shelf
to the right-hand connector in the BA350-SA shelf. This connects
that channel with the SCSI IDs 0, 1, 2, 3, 4, and 5. For example,
to connect channel 1 in the BA350-EA shelf, attach the BN21H
cable from channel 1 to the right-hand connector of the BA350-SA
shelf.
Refer to Figure 7–6.
c.

At this point, the original five drives from the BA350-EA shelf must
be inserted in locations with the same channel and SCSI ID as
originally assigned to the drive. This will allow the operating system
to recognize the original LUNs immediately. The original channel and
SCSI ID assignments were (5,1), (4,2), (3,3), (2,4), and (1,5).
In the new configuration, drive (5,1) is still in the BA350-EA shelf,
while drives (4,2), (3,3), (2,4) and (1,5) must be relocated each to a
BA350-SA shelf. Refer to Figure 7–7.

d. To expand to two ranks, add an additional five drives in the slot
locations designated by the rank-2 list.
These drives must be inserted in the following locations: (5,2) in
the BA350-EA shelf, and (4,1), (3,1), (2,1), and (1,2) in each of the
BA350-SA shelves. Refer to Figure 7–7.
e.

To expand to three ranks, add an additional five drives in the slot
locations designated by the rank-3 list.
These drives must be inserted in the following locations: (5,3) in
the BA350-EA shelf, and (4,3), (3,2), (2,2), and (1,3) in each of the
BA350-SA shelves. Refer to Figure 7–7.

To expand to four ranks, add an additional five drives in the slot
locations designated by the rank-4 list.
These drives must be inserted in the following locations: (5,4) in
the BA350-EA shelf, and (4,4), (3,4), (2,3), and (1,1) in each of the
BA350-SA shelves. Refer to Figure 7–7.

g. To expand to five ranks, add an additional five drives in the slot
locations designated by the rank-5 list.
These drives must be inserted in the following locations: (5,5) in
the BA350-EA shelf, and (4,5), (3,5), (2,4), and (1,1) in each of the
BA350-SA shelves. Refer to Figure 7–7.

Advanced Configurations 7–15

Advanced Configurations
7.4 Recommended Configurations
h. To expand to six ranks, add an additional five drives in the slot
locations designated by the rank-6 list.
These drives must be inserted in the following locations: (5,0) in
the BA350-EA shelf, and (4,0), (3,0), (2,0), and (1,0) in each of the
BA350-SA shelves. Refer to Figure 7–7.
3. Power on the DEC RAID Subsystem.
You have completed the shelf reconfiguration. Verify that you have correctly
reconfigured your BA350-EA with four BA350-SA shelves as described in
Section 7.4.2.3.
7.4.2.3 Post-Reconfiguration
To verify your configuration, use DEC RAID Utilities appropriate for your
operating system to perform the following steps:
1. Verify that original drives are all set to optimal condition.
2. Verify that new drives are displayed as ‘‘spare’’ drives in the proper
array channel/SCSI ID positions.
3. Configure and format desired RAID level configurations.
4. Reboot the system.

7–16 Advanced Configurations

Advanced Configurations
7.4 Recommended Configurations
7.4.3 Expansion from a Single BA350-EA/Dual BA350-SA to a Single
BA350-EA/Quad BA350-SA Configuration
This section describes how to expand your one BA350-EA shelf with two BA350SA shelves to four BA350-SA shelves, expanding from three ranks to a maximum
of six ranks of drives. Each rank contains five drives.

Shelf Requirements: One BA350-EA shelf, Four BA350-SA shelves
This expansion allows you to expand from three ranks of drives (15 drives) to up
to six ranks of drives (30 drives).

Purpose
The single BA350-EA shelf with two BA350-SA shelves configuration contains
three ranks of drives (15 drives). Expansion involves adding additional ranks
of five drives each to the configuration. The single BA350-EA/dual BA350-SA
configuration can contain up to three ranks of drives (15 drives). This expansion
path requires cabling two additional BA350-SA shelves, and relocating the
initial five drives into slots at the same channel and SCSI IDs as in the original
configuration.
To expand your configuration, perform the following sets of tasks:
•

Pre-reconfiguration

•

Shelf reconfiguration

•

Post-reconfiguration

7.4.3.1 Pre-Reconfiguration
Before you begin to expand your configuration, perform the following steps:
1. Back up your data to other media.
2. Figure 7–8 shows your current configuration. Use Figure 7–8 as the guide
for identification information. Label each of your current drives with array
channel and SCSI ID information.

Advanced Configurations 7–17

Advanced Configurations
7.4 Recommended Configurations
Figure 7–8 Single BA350-EA Shelf
TO HOST

0
5 T

4 T

3 T

2 T

1 T

5
(6)
0

(6)
POWER

(7) T

POWER
(7)

LEGEND
BACKPLANE CONNECTION

(6) (7)

TERMINATOR

JUMPER
SCSI CABLE
SLOT NUMBERS
SCSI CHANNEL
CXO-3589B-MC

Note
You can label the SBB in pencil. You can erase the SBB later and relabel
it as needed.

3. Figure 7–9 shows the physical layout of the reconfiguration. Figure 7–10
represents the logical view of the reconfiguration. Study Figure 7–9 and
Figure 7–10 to be certain that you understand the cabling and relocation of
drives. Refer to Chapter 5 to review connection information.
4. Power down the DEC RAID Subsystem.
You are ready to begin the shelf reconfiguration described in Section 7.4.3.2.
7.4.3.2 Shelf Reconfiguration
To expand your configuration, perform the following steps:
1. Reconfigure your BA350-EA shelf and BA350-SA shelves using the diagram
shown in Figure 7–9.

7–18 Advanced Configurations

Advanced Configurations
7.4 Recommended Configurations
Figure 7–9 Single BA350-EA/Dual BA350-SA Shelf to Single BA350-EA/Quad
BA350-SA Shelf Reconfiguration

0
5 T
4
3
2
1

J
2
J
3
J
4
J
5
(6)
0

(6)
POWER
POWER (7) T

JA1

JB1

JA1

JB1

0
T

JA1

JB1

0
T

JA1

JB1

0
T

4
J

(7)

4
J

POWER (7)

SHELF 1

SHELF 2

SHELF 3

SHELF 4
CXO-3594B-MC

To begin, the BA350-EA shelf is reconfigured by removing some of the
terminators and adding jumpers instead. The jumpers and terminators
are located at the back of the unit on the backplane.
•

Add the jumpers at SCSI ID slots 2, 3, 4, and 5. This connects SCSI IDs
1, 2, 3, 4, 5, and 0 to channel 5. Note that SCSI IDs 5 and 0 are connected
through the backplane and no jumper is required.

Refer to Figure 7–10. The channel and SCSI ID are designated as (x,y) or
(channel, SCSI ID). For example, channel 5, SCSI ID 1 is designated as (5,1).

Advanced Configurations 7–19

SCSI IDs 1, 3, 5, and 6

•

SCSI IDs 0, 2, and 4

If a terminator is placed in slot 5 (SCSI ID 5), then the SCSI buses will be
separate. Otherwise, if you put a jumper in slot 5, then the SCSI IDs are all
connected together.
1. For purposes of this configuration, put a terminator in slot 5 as shown in
Figure 7–9. As you continue with the reconfiguration, be certain to follow
the pattern of jumpers and terminators shown in Figure 7–9.
2. Using Figure 7–10 as a guide, perform the following steps:
Figure 7–10 Single BA350-EA/Dual BA350-SA Shelf Configuration to Single
BA350-EA/Quad BA350-SA Drive Reconfiguration

350−E
(5,1) 1
(5,2) 2
(5,3) 3

350−S

350−E

350−S 350−S

350−S

ADD 0
(3,1) 1

ADD 0
(4,1) 1

(1,0) 0

(2,0) 0

(3,1) 1

(4,1) 1

(5,1) 1

ADD 1

2
(3,3) 3

(1,2) 2
(4,3) 3

(5,2) 2

(1,2) 2

ADD 2

(5,3) 3

ADD 3

ADD 2
(3,3) 3

ADD 2
(4,3) 3

ADD 4
ADD 5
ADD 0

(1,4) 4
ADD 5

(2,4) 4
(2,5) 5

ADD 4
(3,5) 5

ADD 4
(4,5) 5

(2,4) 4
(2,5) 5

(1,4) 4

(3,5) 5

(4,5) 5

(2,0) 0

Rank 1: (5,1) (4,1) (3,1) (2,4) (1,0)
Rank 2: (5,2) (4,3) (3,3) (2,5) (1,2)
Rank 3: (5,3) (4,5) (3,5) (2,0) (1,4)
Rank 4: (5,4) (4,4) (3,4) (2,3) (1,5)
Rank 5: (5,5) (4,2) (3,2) (2,2) (1,3)
Rank 6: (5,0) (4,0) (3,0) (2,1) (1,1)

(x,y) = (Channel, SCSI Id)
SHR−XR3018−GRA

a. Connect the BA350-SA shelves to the BA350-EA shelf.
The section of the BA350-EA shelf that contains the HSZ10-AA
controller contains a column of six 50-pin, high-density connectors
on the right-hand side. These connectors are labeled as channels
in Figure 7–8. The top connector is used exclusively for connecting
to host adapter SSBs (for example, the DWZZA-VA) in slot 0, and
that connector is unnumbered in Figure 7–8. The other connectors
are labeled as 5, 4, 3, 2, and 1.
7–20 Advanced Configurations

Advanced Configurations
7.4 Recommended Configurations
The BA350-SA shelf contains two 50-pin high-density connectors
on the backplane at the top of the shelf. If you look at the shelf
from the front, the left-hand connector connects SCSI IDs 0, 2,
and 4. The right-hand connector connects SCSI IDs 1, 3, and 5.
As previously discussed, these SCSI buses are independent of each
other unless you put a jumper in slot 5.
To connect a channel to the BA350-SA shelf, run a cable from
the BA350-EA shelf to the BA350-SA shelf. Use a BN21H
Series cable, which has two 50-pin, high-density, male, straight
connectors.
b. For this configuration, connect channels 1, 2, 3, and 4 from the
BA350-EA shelf to the BA350-SA shelves as follows:
Attach a BN21H cable from the channel in the BA350-EA shelf
to the right-hand connector in the BA350-SA shelf. This connects
that channel with the SCSI IDs 0, 1, 2, 3, 4, and 5. For example,
to connect channel 1 in the BA350-EA shelf, attach the BN21H
cable from channel 1 to the right-hand connector of the BA350-SA
shelf.
Refer to Figure 7–9.
c.

At this point, the original drives in the BA350-EA and BA350-SA
shelves must be inserted in locations with the same channel and SCSI
ID as originally assigned to the drive. This will allow the operating
system to immediately recognize the original LUNs. The original
channel and SCSI ID assignments were as follows:
•

The BA350-EA shelf contained (5,1), (5,2), (5,3), (2,4), (2,5), (2,0).

•

One of the BA350-SA shelves contained (3,1), (3,3), and (3,5).

•

The other BA350-SA shelf contained (1,0), (4,1), (1,2), (4,3), (1,4),
and (4,5).

In the new configuration, drives (5,1), (5,2), and (5,3) are still in the
BA350-EA shelf, while drives (1,0), (1,2), (1,4) must be relocated to the
first BA350-SA shelf, drives (2,0), (2,4), (2,5) to the second BA350-SA
shelf, drives (3,1), (3,3), (3,5) to the third BA350-SA shelf, and drives
(4,1), (4,3), (4,5) to the fourth BA350-SA shelf.
d. To expand to four ranks, add an additional five drives in the slot
locations designated by the rank-4 list.
These drives must be inserted in the following locations: (5,4) in
the BA350-EA shelf, and (4,4), (3,4), (2,3), and (1,5) in each of the
BA350-SA shelves. Refer to Figure 7–10.
e.

To expand to five ranks, add an additional five drives in the slot
locations designated by the rank-5 list.
These drives must be inserted in the following locations: (5,5) in
the BA350-EA shelf, and (4,2), (3,2), (2,2), and (1,3) in each of the
BA350-SA shelves. Refer to Figure 7–10.

To expand to six ranks, add an additional five drives in the slot
locations designated by the rank-6 list.
These drives must be inserted in the following locations: (5,0) in
the BA350-EA shelf, and (4,0), (3,0), (2,1), and (1,1) in each of the
BA350-SA shelves. Refer to Figure 7–10.
Advanced Configurations 7–21

Advanced Configurations
7.4 Recommended Configurations
3. Power on the DEC RAID Subsystem.
You have completed the shelf reconfiguration. Verify that you have correctly
reconfigured your BA350-EA with four BA350-SA shelves as described in
Section 7.4.3.3.
7.4.3.3 Post-Reconfiguration
To verify your configuration, use DEC RAID Utilities appropriate for your
operating system to perform the following steps:
1. Verify that original drives are all set to optimal condition.
2. Verify that new drives are displayed as ‘‘spare’’ drives in the proper
array channel/SCSI ID positions.
3. Configure and format desired RAID level configurations.
4. Reboot the system.

7.5 Custom Expansions
This section outlines the steps used for expanding a configuration that requires
reconfiguration of the array and the rebuilding of user data. Refer to Table 7–1
for details on which expansion paths this includes.
To perform custom expansions, do the following:
Note
It is very important that you back up your data to other media, since this
procedure will destroy your data.

1. Back up your data to other media.
2. Using DEC RAID utilities, perform the following steps:
a. Delete all configured LUNs. This makes all drives spares.
b. Reconfigure drive in array channel 5, SCSI ID 1 to be a 1 drive RAID 0
array.
3. Power down your DEC RAID Subsystem.
4. Refer to Table 7–1 for the appropriate section for reconfiguring your shelves.
5. Power on your DEC RAID Subsystem.
6. Using DEC RAID utilities, perform the following steps:
a. Delete LUN 0 (LUN 0 contains the 1 drive in Channel 5, SCSI ID 1)
configured in Step 2.
b. Configure and format desired RAID level configurations. To maintain your
data, you must conform to the drive mappings detailed in Sections 7.4.1
through 7.4.3. When you elect to use the customized expansion technique
detailed here, your data is not maintained. Therefore, you do not need
to conform to the drive mappings shown in Sections 7.4.1 through 7.4.3
because you are using this customized expansion technique.

7–22 Advanced Configurations

8
Error Handling/Troubleshooting
This chapter contains troubleshooting information to correct problems that may
be easy to fix. It also directs you to the appropriate documentation for additional
troubleshooting information if needed.
This chapter discusses the following:
•

Before you begin troubleshooting

•

Using the troubleshooting table

•

If you have expanded your DEC RAID Subsystem

8.1 Before You Begin Troubleshooting
To determine where the problem with your DEC RAID Subsystem exists, follow
these steps:
1. Turn off the DEC RAID Subsystem.
2. Turn off the host system.
3. Check to see that the cables are correctly connected including the following:
•

68-pin SCSI ‘‘P’’ Cable connected to HSZ10-AA controller

•

Terminator

•

SCSI cable connected to host system

•

50-pin SCSI cables to BA350-SA shelves (if applicable)

4. Turn the DEC RAID Subsystem back on.
5. Verify that all the drive SBBs LED indicators flash on initial power on.
6. Verify that the two LED indicators on the power supplies are lit.
7. Verify that the HSZ10-AA controller LEDs indicators flash and the controller
begins its diagnostics.

8.2 Using the Troubleshooting Table
When the DEC RAID Subsystem does not operate correctly, use the information
in this section to help diagnose the problem.
The troubleshooting techniques described do not identify all possible problems
with the subsystem, nor do the corrective actions suggested remedy all problems.
To use Table 8–1, follow these steps:
1. Note the symptoms of the problem with your DEC RAID Subsystem.
2. Check the Symptom column in Table 8–1 for a match.

Error Handling/Troubleshooting 8–1

Error Handling/Troubleshooting
8.2 Using the Troubleshooting Table
3. Check the conditions for that symptom in the Possible Cause column. If more
than one possible cause is given, check all of the possible causes in the order
listed.
4. Follow the advice in the Corrective Action column.
Table 8–1 Troubleshooting Systems Problems
Symptom

Possible Cause

Corrective Action

Drive SBB Fault Light is on.

Drive has failed.

Replace drive using
instructions in
Chapter 6, Section 6.3.

Drive SBB Fault and Activity
Lights are on.

Drive has failed or is hung.

Replace drive using
instructions in
Chapter 6, Section 6.3.

Drive SBB Fault Light is
flashing.

Drive has been failed and is
spinning down.

Replace drive using
instructions in
Chapter 6, Section 6.3.

Replaced Drive has not spun
up.

Drive not seen by HSZ10-AA
controller.

Remove drive SBB, wait
10 seconds, reinsert drive
SBB.

Power Supply SBB shelf
status light is off.

Shelf Fault.

Refer to Chapter 6,
Section 6.2 and
Section 6.4, for
description of fault
condition and resolution.

Both lights off on Power
Supply.

Input power problem.

Check for proper
connection of input
power.

Shelf and Power Supply
Fault.

Refer to Chapter 6,
Section 6.2 and
Section 6.4, for
description of fault
condition and resolution.

Controller is not properly
installed.

Remove and reseat
controller using the
guidelines in the HSZ10AA Controller Site
Preparation Guide.

HSZ10-AA controller has
failed.

Replace controller using
guidelines in the HSZ10AA Controller Site
Preparation Guide.

SCSI cable is not connected.

Check the SCSI cable
both at the host and DEC
RAID Subsystem ends
for proper connection.

Incorrect termination.

Check that both ends of
SCSI bus are terminated
correctly. Verify that
proper termination
scheme is being used
(see Chapter 5).

HSZ10-AA controller LED
indicators are off.

DEC RAID Subsystem is not
seen by host.

(continued on next page)

8–2 Error Handling/Troubleshooting

Error Handling/Troubleshooting
8.2 Using the Troubleshooting Table
Table 8–1 (Cont.) Troubleshooting Systems Problems
Symptom

Software does not boot from
the DEC RAID Subsystem.

Possible Cause

Corrective Action

Duplicate SCSI IDs on bus.

Check SCSI ID settings
on all devices connected
to bus for duplication.
Run bus scan console
diagnostics if they are
available on your host
system.

Defective HSZ10-AA
controller.

Refer to Chapter 6,
Section 6.2, for a
description of the
possible LED status.
Determine whether
controller has failed.
Replace the controller if
needed.

A problem exists with the
DEC RAID Subsystem.

Use any available system
console diagnostics or the
DEC RAID utilities
to test DEC RAID
Subsystem.

A problem exists with the
software installed on the
DEC RAID Subsystem.

Refer to the DEC RAID
Utilities User’s Guide for
help.

8.3 If You Have Expanded Your DEC RAID Subsystem
If you have attempted an expansion of your DEC RAID Subsystem, follow these
steps to determine the problem:
1. Turn off the DEC RAID Subsystem.
2. Turn off the host system.
3. Check that the reconfiguration of the shelves has been done correctly
according to the shelf reconfiguration diagrams in Chapter 7.
•

Check that jumpers are placed in proper locations.

•

Check that terminators are placed in proper locations.

4. Check to see that the cables are correctly connected, including the following:
•

68-pin SCSI ‘‘P’’ Cable connected to HSZ10-AA controller

•

Terminator

•

SCSI cable connected to host system

•

50-pin SCSI cables to BA350-SA shelves (if applicable)

5. Check that drive movement and drive addition have been done correctly.
Refer to Chapter 7.
6. Turn the DEC RAID Subsystem back on.
7. Verify that all the drive SBBs LED indicator flash on initial power on.
8. Verify that the two LED indicators on the power supplies are lit.

Error Handling/Troubleshooting 8–3

Error Handling/Troubleshooting
8.3 If You Have Expanded Your DEC RAID Subsystem
9. Verify that the HSZ10-AA controller LEDs indicators flash and the controller
begins its diagnostics.
10. Use the DEC RAID utilities to determine the status of the LUN and drive.

8–4 Error Handling/Troubleshooting

A
Physical Specifications
This appendix describes the physical, environmental, and performance
specifications for the DEC RAID Subsystem product. For additional StorageWorks
component specifications, refer to the StorageWorks Subsystem Shelf Building
Block Configuration Guide.

A.1 General Specifications
Table A–1 SZ200 General Specifications
Dimensions
(height width

depth)

610 mm
24 in

508 mm
20 in

368 mm

14.5 in

Power Supply

Standard - 262 W (2 BA35X-HA)

Operating Temperature

+10°C to +40°C (+50°F to +104°F)

The standard power option for the DEC RAID Subsystem is two power supplies.
However, the power supply SBB is rated at 131 watts and sufficient power for a
fully loaded shelf.

A.2 Power Unit Specifications
Each StorageWorks shelf requires either a primary ac or dc power unit. The
power unit type is determined the by the enclosure ac power distribution unit or
dc power controller.
All shelves can have a redundant power unit to ensure that a power unit
failure does not disable the shelf. In most cases, battery backup units can be
combined with the primary power unit to ensure that in the event of a power unit
failure the integrity SBB data is maintained while the devices power down. See
Table A–2 and StorageWorks Shelf Building Block Subsystem User’s Guide for
more information about the power units.

Physical Specifications A–1

Physical Specifications
A.2 Power Unit Specifications
Table A–2 StorageWorks Power Units
Specifications

BA35X–HA

BA35X–HB

BA35X–HC

Power unit type

ac input

dc input

Battery Backup

Input voltage range

90–264 Vac

36–72 Vdc

N/A

Nominal input voltage

110 Vac

48 Vdc

12 Vdc

Autoranging feature

Yes

N/A

Output voltages

12 Vdc
5 Vdc

N/A

Output power†

131 W

N/A

† Sequential device spin-up at 9 second interval mandatory.

A.3 Environmental Stabilization
To ensure proper operation of Digital storage devices, the SBB temperature must
be within 18°C to 29°C (65°F to 85°F). Table A–3 specifies the time required to
thermally stabilize SBBs based on the ambient shipping temperature.
CAUTION
Always stabilize storage devices in the operating environment prior to
installation or operation. Otherwise, the media or associated electronics
may be damaged when power is applied to the unit.
If condensation is visible on the outside of the storage device:
Stabilize the device and the SBB in the operating environment for 6 hours or
until the condensation is no longer visible, whichever is longer. Do not insert
the storage device into the shelf until it is fully stabilized.
If condensation is not visible on the outside of the storage device:
Thermally stabilize the device for the amount of time specified in Table A–3.
Table A–3 Thermal Stabilization Specifications
Ambient
Temperature
Range °C

Ambient
Temperature
Range °F

Minimum
Stabilization
Time

60 to 66
50 to 59
40 to 49
30 to 39
18 to 29
10 to 17
0 to 9
–10 to –1
–20 to –11
–30 to –21
–40 to –31

140 to 151
122 to 139
104 to 121
86 to 103
65 to 85
50 to 64
32 to 49
14 to 31
–4 to 13
–22 to –5
–40 to –21

3 hours
2 hours
1 hour
30 minutes
None
30 minutes
1 hour
2 hours
3 hours
4 hours
5 hours

A–2 Physical Specifications

Physical Specifications
A.4 Environmental Specifications

A.4 Environmental Specifications
The StorageWorks product line environmental specifications listed in Table A–4
are the same as for other Digital storage devices.
Table A–4 Environmental Specifications
Condition

Specification

Optimum Operating Environment
Temperature
Rate of change
Step change

+18°C to +24°C (+65°F to +75°F)
3°C (5.4°F)
3°C (5.4°F)

Relative humidity

40% to 60% (noncondensing) with a step change of 10% or less
(noncondensing)

Altitude

From sea level to 2400 m (8000 ft)

Air quality

Maximum particle count .5 micron or larger, not to exceed 500,000
particles per cubic ft of air

Inlet air volume

.026 cubic m per second (50 cubic ft per minute)

Maximum Operating Environment (Range)
Temperature

+10°C to +35°C (+50°C to +95°F)
Derate 1.8°C for each 1000 m (1.0°F for each 1000 ft) of altitude
Maximum temperature gradient 11°C/hr (20°F/hr) ±2°C/hr (4°F/hr)

Relative humidity

10% to 90% (noncondensing)
Maximum wet bulb temperature: 28°C (82°F)
Minimum dew point: 2°C (36°F)

Maximum Nonoperating or Storage Environment (Range)
Temperature
Nonoperating
Storage
Relative humidity
Nonoperating
Storage
Altitude

+18°C to +29°C (+65°F to +85°F)
–40°C to +66°C (–40°F to +151°F)
10% to 90% (noncondensing)
8% to 95% in original shipping container (noncondensing);
otherwise, 50% (noncondensing)
From -300 m (-1000 ft) to +3600 m (+12,000 ft) MSL

Physical Specifications A–3

B
Supported Options
This appendix includes information regarding the disk drives and adapters
supported by the system. Table B–1 describes the disk drives supported by the
system.
Table B–1 Disk Drives Supported
Component

Description

RZ25

426 Mbyte SCSI Disk Drive

RZ26

1.05 Gbyte SCSI Disk Drive

Table B–2 describes the adapters supported by the system.
Table B–2 Adapters Supported
Component

Description

KZESA

EISA/SCSI Differential Host Adapter

DWZZA-VA

Single-ended to Differential/Wide SCSI Adapter

Supported Options B–1

C
Operating System Support
This appendix contains information regarding the operating systems supported
by the DEC RAID Subsystem and part numbers associated with the DEC RAID
Subsystem.
Table C–1 lists the operating systems.
Table C–1 Operating Systems Supported
Operating System

O/S Version with DEC RAID Subsystem Support

NOVELL

3.11

SCO UNIX

3.2.4

MS–DOS

3.3, 5.0

OpenVMS VAX

V5.5-2

Operating System Support C–1

D
System Connections
Table D–1 describes the type of connectivity for various system adapters to
help you determine cabling requirements for systems. Refer to the appropriate
sections in this manual based on the type of connectivity described in Table D–1.
Table D–1 is provided for informational purposes only. You should not assume
that this is a complete listing of systems. Nor should you assume that the all
systems listed here are fully qualified or supported. Please contact your local
sales representative to verify support on a particular system or operating system
platform.
Table D–1 System Connectivity
System

SCSI Adapter

Refer to:

Model 30

Embedded SCSI

Section 5.1.4

Model 40

Embedded SCSI

Section 5.1.4

Model 80

Embedded SCSI

Section 5.1.4

Model 90

Embedded SCSI

Section 5.1.4

Model VLC

Embedded SCSI

Section 5.1.4

Model 60

Embedded SCSI

Section 5.1.4

Model 60

PMAZ

Section 5.1.4

Model 90

Embedded SCSI

Section 5.1.4

Model 90

PMAZ

Section 5.1.4

Embedded SCSI

Section 5.1.4

433MP

KZESA

Section 5.1.3

400XP

KZESA

Section 5.1.3

KZESA

Section 5.1.3

MicroVAX 3100

VAXstation 4000

VAX System 4000
Model 100
applicationDEC

DECpc
425ST

(continued on next page)

System Connections D–1

System Connections

Table D–1 (Cont.) System Connectivity
System

SCSI Adapter

Refer to:

433ST

KZESA

Section 5.1.3

450ST

KZESA

Section 5.1.3

D–2 System Connections

Glossary
ac distribution
The method of controlling ac power in a cabinet.
adapter
(1.) A connecting device that permits the attachment of accessories or provides
the capability to mount or link units.
(2.) The device that connects an 8-bit differential SCSI bus to an 8-bit
single-ended SCSI bus.
array
A set of multiple disk drives and a specialized controller, an array controller,
which keeps track of how the data is distributed across the drives.
array channels
The SCSI-2 compliant buses on which the disk drives are located. Each array
channel is an independent SCSI bus.
array controller
A device that exercises control over the SCSI bus (for example, an HSZ10–AA
disk array controller).
BA35X–VA
A collective reference to all versions of the vertical mounting kits—single and
double.
Battery Backup Unit (BBU)
StorageWorks power unit option that provides sufficient power to prevent storage
devices from losing data in the event of a shelf power unit failure.
Note
The BBU does not provide power for the operation of a storage device.
The BBU provides power only for protecting data.

CI
A Digital trademark for the Digital Computer Interconnect bus.

Glossary–1

cold-swapping
A method of device replacement that requires that the power be removed from all
shelves in a cabinet. This method is used when conditions preclude the use of a
warm-swapping or hot-swapping method.
See also warm-swapping and hot-swapping.
controller
A hardware line device that manages communications over a line. Controllers
can be point-to-point, multipoint, or multiple line.
dc power system
The method for providing dc power in a cabinet.
double stand
A BA35X–VA vertical mounting kit composed of two single stands clipped
together. This configuration can support one BA350–EA shelf.
See also single stand.
drive group
A set of 1 to 10 drives that have been configured into one or more logical units. A
logical unit can be contained in only one drive group, and all the logical units in
a drive group must have the same RAID level and be of the same drive type.
drive rank
Drive ranks represent a numbering scheme that provides information on
the maximum number of drives on every array channel. A one-rank system
indicates that there is a maximum of one drive per disk channel. A two-rank
array indicates that there is a maximum of two drives per disk array channel.
However, any channel can have zero for its maximum number.
DSSI
Digital Storage System Interconnect.
FD SCSI
The fast, differential SCSI bus with an 8-bit data transfer rate of 10 MB/s.
See also FWD SCSI and SCSI.
FWD SCSI
The fast, wide, differential SCSI bus with a 16-bit data transfer rate of 20 MB/s.
See also FD SCSI and SCSI.
H981X
A collective reference to the H9810 (short), H9811 (medium), and H9812 (tall)
towers.
Heartbeat LED
The bottommost LED on the HSZ10-AA controller. Beats once per second.
host
The primary or controlling computer in a multiple computer network.

Glossary–2

hot-swapping
A method of device replacement whereby the complete system remains online and
active during device removal or insertion. The device being removed or inserted
is the only device that cannot perform operations during this process.
See also cold-swapping and warm-swapping.
LUNs (logical units)
A logical unit is a grouping of drives that has its own device SCSI ID and
number. Each logical unit has its own array parameters (RAID level, segment
size, and so on). For most purposes, a logical unit is equivalent to an array.
mirrored
A copy of data on a disk or a set of disks. Refer to the description of RAID 1.
parity check/repair
The process of verifying and repairing parity information so that data can be
maintained and reconstructed in the event of a drive failure. Parity Check/Repair
functionality is provided by the DEC RAID utilities.
RAID
A redundant array of inexpensive disks.
rank
The number of drives per channel. See also drive rank.
redundancy
Also data redundancy. Data stored on another physical disk that can be used to
recover data if the physical disk containing the data cannot be accessed.
SBB
System building block. A modular carrier plus the individual mechanical and
electromechanical interface required to mount it into a standard shelf. Any
device conforming to shelf mechanical and electrical standards is considered an
SBB.
SCSI
Small Computer System Interface. This interface defines the physical and
electrical parameters of a parallel I/O bus used to connect computers and
a maximum of seven SBBs. The StorageWorks modular storage system
implementation uses SCSI–2, which permits the synchronous transfer of 8-bit
data at rates of up to 10 MB/s.
segment
A group of blocks that is continuous data which can be stored on a disk drive.
shelf array
A modular storage shelf that provides power, cooling, interconnects, and
mounting for SBBs. Specific shelves are denoted by the prefix BA350 (that is,
BA350–RA, BA350–SA, and so on). Shelves may be mounted in kits, towers, or
cabinets.

Glossary–3

single stand
A reference to the basic BA35X–VA vertical mounting kit with a capacity of one
BA350–SA shelf.
See also double stand.
Small Computer System Interface
See SCSI.
stands
A collective reference to all versions of the vertical mounting kits—both single
and double.
static storage device (SSD)
An electronic storage device such as the EZ51R–VA.
StorageWorks
The mnemonic for the Digital Storage/Modular Enclosure, a modular set of
enclosure products that allows customers to design their own storage array.
Components include power, packaging, and interconnections in a modular storage
shelf into which SBBs (system building blocks) and array controller modules are
integrated to form modular storage arrays. System-level enclosures to house the
arrays and standard mounting devices for SBBs are also included.
striped
See the description of RAID 0 in the DEC RAID Subsystem User’s Guide.
system building block
See SBB.
towers
A collective reference to the H9810 (short), H9811 (medium), and H9812 (tall)
towers.
warm-swapping
A method of device replacement in which the complete system remains online
during device removal or insertion. The system bus may be halted for a brief
period of time, during device insertion or removal. No booting or loading of code
is permitted except on the device being inserted.
See also cold-swapping and hot-swapping.

Glossary–4

Index
A
Adapters description, B–1
Advanced configurations, 7–1
Array
channels, 3–6
definition, 3–1
features, 1–3, 2–4
Audience, ix

B
BA350-EA shelf description, 2–2
BA35X-VA description, 2–1
Basic configuration
modifying, 7–1
Blower replacement, 6–12
Bus connections
end-bus, 5–4
midbus, 5–4
Bus continuity
maintaining, 5–4

C
Cable options, 2–5
Cables, verifying, 5–5
Capacity, 1–5
Cold swapping, 6–11
Component descriptions, 2–1
Configurations
advanced, 7–1
guidelines, 7–2
multiple rank, 7–2
Connecting
to a 16-bit differential host/adapter, 5–2
to a host, 5–1
to an 8-bit differential host/adapter, 5–2
to an 8-bit single-ended host/adapter, 5–3
Connectors, verifying, 5–5
Cost
of single-drive failure, 1–5
Custom expansion, 7–22

D
Data
availability, 1–4
mirrored, 3–2
reliability, 1–3
segmented, 3–1
DEC RAID Subsystem
capacity, 1–5
component descriptions, 2–1
data availability, 1–4
data reliability, 1–3
flexibility, 1–5
logical view, 1–2
monitoring features, 6–1
performance, 1–4
physical specifications, A–1
product attributes, 1–3
product description, 1–1
product highlights, 1–3
product overview, 1–1
redundancy, 1–4
DEC RAID utilities, 2–5
monitoring through, 6–4
Disk array description, 3–1
Disk array subsystems descriptions, B–1
Documentation
related, x
Drive
groups, 3–7
how to replace, 6–10
ranks, 3–7
SBB LED indicators, 6–8
status, 6–3
DWZZA-VA, 4–4
features, 4–4

E
Environmental specifications, A–3
Environmental stabilization, A–2
Error handling, 8–1
Expansion paths
custom expansion, 7–22
from 1 BA350-EA/2 BA350-SA to 1 BA350-EA/4
BA350-SA, 7–17

Index–1

Expansion paths (cont’d)
from 1 BA350-EA to 1 BA350-EA/2 BA350-SA,
7–5
from 1 BA350-EA to 1 BA350-EA/4 BA350-SA,
7–11
recommended, 7–4
table of, 7–4
types of, 7–3
Expansion unit description, 2–5

F
Features
array, 1–3
subsystem, 1–3
Firmware, 2–4
Flexibility, 1–5

H
Hot swapping, 6–11
HSZ10-AA controller
description, 2–2
features, 2–3
LED codes, 6–5
LED indicators, 6–5
location and SCSI address, 4–3
monitoring through, 6–1

I
Installation, 5–1

L
LED indicators
monitoring through, 6–5
LEDs
drive SBB, 6–8
HSZ10-AA controller, 6–5
HSZ10-AA controller codes, 6–5
power supply, 6–7
power supply and shelf, 6–8
shelf and power supply, 6–8
types of, 6–5
Logical drive map, 4–4
Logical units (LUNs)
description, 3–6
modes of operation, 3–6
LUNs
definition, 3–2
LUN status, 6–1

M
Mirrored data, 3–2
Monitoring
operations with LED indicators, 6–5
operations with the DEC RAID utilities, 6–4
through the HSZ10-AA controller, 6–1
through the StorageWorks shelf, 6–4
user monitoring methods, 6–4

O
Operating systems supported, C–1
Operations, 6–1
Overview, 1–1

P
Parity check/repair, 6–14
Partitions, 3–7
Performance, 1–4
Physical drive map, 4–4
Powering on
the subsystem, 5–6
Power supply
how to replace, 6–11
LED indicators, 6–7
specifications, A–1
Power supply and shelf
LED indicators, 6–8
Power unit
specifications, A–1
Product
attributes, 1–3
description, 1–1
highlights, 1–3
overview, 1–1
Purpose, ix

R
RAID 0 description, 3–2
RAID 1 description, 3–3
RAID 3 description, 3–4
RAID 5 description, 3–5
RAID overview, 3–1
Reconstruction, 3–8, 6–13
Redundancy, 1–4
Regeneration, 3–8
Related documents, x

S
SBBs, 2–4
adapter SBBs, 2–5
disk SBBs, 2–4
power SBBs, 2–4

Index–2

SCSI driver support, 2–5
SCSI interconnects/host adapters, 2–5
Segment, 3–1
Shelf and power supply
LED indicators, 6–8
Shelf power supply
replacing, 6–11
Software, 2–4
Software, upgrading, 6–15
Specifications
environmental, A–3
environmental stabilization, A–2
for DEC RAID Subsystem, A–1
general, A–1
power supply, A–1
power unit, A–1
Status
drive, 6–3
LUN, 6–1
StorageWorks shelf
monitoring through, 6–4
Subsystem features, 1–3
Swapping
cold, 6–11
hot, 6–11
warm, 6–11

SZ200
physical arrangement of the base configuration,
4–4
SZ200 base configuration, 4–1
SZ200 description, 2–1

T
Temperature
ranges, A–2
Terminating
the SCSI bus, 5–1
Thermal stabilization, A–2
Troubleshooting, 8–1
table of, 8–2

V
Verifying cables and connectors, 5–5
Verifying functionality, 5–6
Vertical mounting kit description, 2–1

W
Warm swapping, 6–11

Index–3