DEC RAID Subsystem User's Guide

This document is a User's Guide for the DEC RAID Subsystem, published by Digital Equipment Corporation in 1993. It serves as a comprehensive manual for customers, system administrators, and service engineers responsible for installing, configuring, and maintaining the system.

Key aspects covered in the guide include:

1. Product Description:

   • Purpose: Introduces the DEC RAID Subsystem as a modular, integrated, and highly available storage solution leveraging RAID technology, redundant components, software utilities, and SCSI interconnects.
   • Features & Attributes: Highlights support for RAID levels 0, 1, 3, and 5; hot-swapping of drives and controllers; up to 35 disk drives; and redundant power supplies and blowers. It emphasizes data reliability, availability, performance, flexibility, and capacity.

2. Component Descriptions:

   • Details the SZ200 base unit, comprising the BA35X-VA mounting kit, BA350-EA shelf, and the central HSZ10-AA controller (an intelligent SCSI disk array controller supporting RAID levels and up to 35 devices).
   • Describes System Building Blocks (SBBs) like power supplies, disk drives, and adapters, emphasizing their modular and hot-swappable design.
   • Covers expansion units (BA350-SA shelves), DEC RAID Utilities (for configuration, monitoring, diagnosis), enhanced SCSI driver support, and various SCSI interconnects/host adapters.

3. RAID Overview:

   • Explains fundamental RAID concepts, defining a disk array, and detailing how data is stored (segmented, mirrored, striped).
   • Provides descriptions of RAID 0 (striping), RAID 1 (mirroring), RAID 3 (parallel transfer with dedicated parity), and RAID 5 (distributed parity), outlining their performance and redundancy characteristics.
   • Defines key terminology such as Logical Units (LUNs), Array Channels, Drive Groups, Drive Ranks, Partitions, Reconstruction, and Regeneration.

4. Configuration & Operations:

   • Base Configuration (SZ200): Details the factory pre-configuration (RAID 5, 5 drives, 1 logical unit) and how to modify it. Includes information on SCSI ID assignments.
   • Installation: Guides users through connecting the subsystem to a host, SCSI bus termination, powering on, and performing functional verification using LED indicators.
   • Maintenance: Describes monitoring features (via controller and LEDs) and step-by-step procedures for hot-swapping and replacing drives, power supplies, and blowers.
   • Data Integrity: Explains Reconstruction (rebuilding data on a replaced drive) and Parity Check/Repair functions for redundant RAID levels.

5. Advanced Configurations & Troubleshooting:

   • Expansion: Provides guidelines and recommended paths for expanding the system to multiple ranks and more drives (up to 35), detailing pre- and post-reconfiguration steps, and noting when data backup is required.
   • Troubleshooting: Offers a table of symptoms, possible causes, and corrective actions for common system problems, including those encountered after system expansion.

Appendices provide technical specifications (physical, environmental), lists of supported disk drives and adapters, and compatible operating systems (e.g., Novell, SCO UNIX, MS-DOS, OpenVMS VAX).