HSG80 Array Controller ACS Version 8.4 Configuration and CLI Reference Guide

This document, titled "HSG80 Array Controller ACS Version 8.4 Configuration and CLI Reference Guide," is a comprehensive manual published by Compaq Computer Corporation in April 1999. It provides detailed information on the features, configuration procedures, and command-line interface (CLI) commands for the Compaq HSG80 Array Controller subsystem running Array Controller Software (ACS) Version 8.4F.

Key Areas Covered:

1. General Description of the HSG80 Subsystem:

   • Outlines major components such as the BA370 enclosure, controllers, cache modules, external cache batteries (ECBs), environmental monitoring unit (EMU), and I/O modules.
   • Summarizes controller features including supported failover modes (Transparent and Multiple-Bus), Fibre Channel Switched Fabric (FC-SW) topology, SCSI protocols (SCSI-2, SCSI-3 for OpenVMS), various disk drive types (Ultra SCSI), and supported RAID levels (0, 1, 0+1, 3/5).
   • Details cache module memory configurations (up to 512MB) and the role of ECBs in preserving write-back cache data during power failures.
   • Introduces various utilities and exercisers for troubleshooting and maintenance, such as Fault Management Utility (FMU), Disk Inline Exerciser (DILX), Configuration Utility (CONFIG), and Code Load and Code Patch Utility (CLCP).

2. Controller and Host Concepts:

   • Explains terminology related to controllers (e.g., "this controller," "other controller," "unresponsive," "surviving").
   • Provides in-depth understanding of Failover Modes, distinguishing between Transparent Failover (seamless automatic takeover with shared host port IDs) and Multiple-Bus Failover (host-assisted failover with separate active host port IDs, allowing host drivers to manage paths).
   • Details Caching Techniques (Read, Read-ahead, Write-through, Write-back) and their fault-tolerance mechanisms, including cache policies and ECB status implications.

3. Controller and Host Addressing:

   • Describes the "bus dynamics" between the host and storage devices, distinguishing between the host bus and controller device bus.
   • Introduces Containers and Storagesets as implementations of RAID technology (e.g., Stripesets, Mirrorsets, RAIDsets) and explains how physical devices are mapped to host-accessible logical units (LUNs).
   • Covers concepts like Port-Target-LUN (PTL) addressing, assigning unit numbers in different failover modes, unit offsets for hosts with limited LUN ranges, and assigning access paths to restrict host access.
   • Explains Controller and Port Worldwide Names (Node IDs) and Unit World Wide Names (LUN IDs) in a Fibre Channel environment.

4. Planning and Configuring Storagesets:

   • Guides users through the planning process, including determining storage requirements, choosing appropriate storageset types (with a comparison of different RAID levels), and creating a "storageset map" for visual organization.
   • Discusses partitioning storagesets and disk drives, including limitations (e.g., not supported in multiple-bus failover).
   • Explains various "switches" (configurable options) for RAIDsets, Mirrorsets, Devices, and Units, such as replacement policy, reconstruction policy, copy speed, read source, transportability, and chunk size.
   • Details procedures for Cloning Data for Backup using the CLONE utility and Backing Up Subsystem Configuration to disk.

5. Configuring the HSG80 Array Controller:

   • Provides step-by-step instructions for configuring the controller in single, transparent failover, and multiple-bus failover modes, including detailed cabling diagrams.
   • Includes optional configuration steps like changing the CLI prompt, setting PVA module ID switches, and configuring power backup with a UPS.
   • Covers procedures for shutting down and restarting the subsystem.

6. Configuring Storagesets with CLI Commands:

   • Offers practical guidance on configuring storagesets using CLI commands, including adding and formatting disk drives, creating various storageset types (Stripesets, Mirrorsets, RAIDsets, Striped Mirrorsets, Single-Disk Units), partitioning, managing sparesets, enabling autospare, and deleting storagesets.
   • Explains how to use the Command Console LUN (CCL) for host-based controller communication and its behavior in SCSI-2 and SCSI-3 modes.
   • Provides a procedure for "moving storagesets" between subsystems.

7. CLI Commands Reference:

   • A comprehensive reference section detailing the syntax, parameters, switches, and examples for almost all available CLI commands. This includes commands for managing connections, disks, mirrorsets, RAIDsets, remote copy sets, sparesets, stripesets, and logical units, as well as commands for error handling, configuration management (reset, restore, save), diagnostics, and controller settings.

Target Audience: This document is intended for system administrators, storage professionals, and technical support personnel responsible for the installation, configuration, troubleshooting, and daily management of the Compaq HSG80 Array Controller subsystem. It assumes familiarity with storage area network (SAN) concepts, Fibre Channel, and SCSI technologies.