Compaq HSZ80 User Manual

HSZ80 Array Controller ACS Version 8.3

Configuration and CLI Reference Guide

First Edition (December 1998) Part Number EK-HSZ80-RG. A01/388222-001 Compaq Computer Corporation

While Compaq Computer Corpo ration belie v es the informat ion included in this manual i s correct as of th e date of publication, it is subject to change without notice. Compaq makes no representations that the interconnection of its products in the manner described in this document will not infringe existing or future patent rights, nor do the descriptions contained in this document imply the granting of licenses to make, use, or sell equipment or software in accordance with the description. No respon sibi lity is assumed for the use or reliabili ty of firmware on equipment not supplied by Compaq or its affiliated companies. Possession, use, or copying of the software or firmware described in this documentation is authorized only pursuant to a valid written license from Compaq, an authorized sublicensor, or the identified licensor.

Commercial Computer Software, Computer Software Documentation and Technical Data for Commercial Items are licensed to the U.S. Government with Compaq’s standard commercial license and, when applicable, the rights in DFAR 252.22 7 70 15 , "Tec hn ic al Da ta -C omm erc ia l I te ms."

Compaq, the Compaq logo, DIGITAL, DIGITAL UNIX, DECconnect, HSZ, HSG, StorageWorks, VMS, OpenVMS Registered in the United States Patent and Trademark Office.

UNIX is a registered trademark in the United States and other countries exclusively through X/Open Company Ltd. Windows NT is a registered trademark of the Microsoft Corporation. Sun is a registered trademark of Sun Microsystems, Inc. Hewlett-Packard, TACHYON, and HP-UX are registered trademarks of the Hewlett-Packard Company. IBM and AIX are registered trademarks of International Business Machines Corporation. All other trademarks and registered trademarks are the property of their respective owners.

This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the manuals, may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his own expense. Restrictions apply to the use of the local-connection port on this series of controllers; failure to observe these restrictions may result in harmful interference. Always disconnect this port as soon as possible after completing the setup operation. Any changes or modifications made to this equipment may void the user's authority to operate the equipment.

Warning! This is a Class A product. In a domestic environment this product may cause radio interference in which case the user may be required to take adequate measures.

Achtung! Dieses ist ein Gerät der Funkstörgrenzwertklasse A. In Wohnbereichen können bei Betrieb dieses Gerätes Rundfunkstörungen auftreten, in welchen Fällen der Benutzer für entsprechende Gegenmaßnahmen verantwortlich ist.

Attention! Ceci est un produit de Classe A. Dans un environnement domestique, ce produit risque de créer des interférences radioélectriques, il appartiendra alors à l'utilisateur de prendre les mesures spécifiques appropriées.

JAPAN

USA

This equipment gener ates, uses, an d may emit r adio fr equenc y en er gy. The equip ment ha s been ty pe test ed and found to comply with the limits for a Class A digital device pursuant to Part 15 of FCC rules, which are designed to provide reasonable protection against such radio frequency interference. Operation of this equi pment in a residential area may cause interference in which case the user at his own expense will be required to take whatever measures may be requir e d to correct the interference. Any modifications to this device - unless expressly approved by the manufacturer - can void the user’ s authority to operate this equipment under part 15 of the FCC rules.

About This Guide

Getting Help. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv

Precautions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvi

Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xviii

Required Tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xx

Related Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxi

Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxii

Chapter 1

General Description

Typical Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–2

Summary of HSZ80 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–5

The HSZ80 Array Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–7

Cache Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–18

External Cache Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–29

Chapter 2

Configuring an HSZ80 Array Controller

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–2

Configuring an HSZ80 Array Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–3

Setting the PVA Module ID Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–25

Establishing a Local Connection to the Controller . . . . . . . . . . . . . . . . . . . . . . . . 2–26

Selecting a Failover Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–29

Enabling Mirrored Write-Back Cache. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–31

Setting SCSI Target ID Numbers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–33

Using Preferred ID Numbers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–35

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

Chapter 3

Creating Storagesets

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–2

Planning and Configuring Storagesets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–4

Creating a Storageset and Device Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–5

Determining Storage Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–7

Choosing a Storageset Type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–8

Cloning Data for Backup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–20

Backing Up Your Subsystem Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–25

Node IDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–30

Assigning Unit Numbers for Host Access to Storagesets . . . . . . . . . . . . . . . . . . . 3–32

Creating a Storageset Map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–34

Planning Partitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–40

Choosing Switches for Storagesets and Devices . . . . . . . . . . . . . . . . . . . . . . . . . . 3–42

RAIDset Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–43

Mirrorset Switches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–45

Device Switches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–48

Initialize Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–51

Unit Switches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–58

Chapter 4

Configuring Storagesets

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4–2

Configuring with the Command Console LUN. . . . . . . . . . . . . . . . . . . . . . . . . . . 4–19

Configuring Units with Multiple Hosts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4–23

Moving Storagesets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4–35

Chapter 5

CLI Commands

CLI Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–2

ADD DISK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–7

ADD MIRRORSET. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–11

ADD PASSTHROUGH. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–16

ADD RAIDSET. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–19

ADD SPARESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–23

ADD STRIPESET. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–24

ADD UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–27

CLEAR_ERRORS CLI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–35

CLEAR_ERRORS controller INVALID_CACHE. . . . . . . . . . . . . . . . . . . . . . . . 5–36

CLEAR_ERRORS device-name UNKNOWN . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–38

CLEAR_ERRORS unit-number LOST_DATA. . . . . . . . . . . . . . . . . . . . . . . . . . . 5–40

CLEAR_ERRORS unit-number UNWRITEABLE_DATA . . . . . . . . . . . . . . . . . 5–42

CONFIGURATION RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–44

CONFIGURATION RESTORE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–45

CONFIGURATION SAVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–47

CREATE_PARTITION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–48

DELETE container-name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–51

DELETE FAILEDSET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–53

DELETE SPARESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–54

DELETE unit-number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–55

DESTROY_PARTITION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–57

DIRECTORY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–59

HELP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–60

INITIALIZE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–62

LOCATE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–67

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MIRROR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–70

POWEROFF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–74

REDUCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–77

RENAME. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–81

RESTART controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–83

RETRY_ERRORS unit-number UNWRITEABLE_DATA . . . . . . . . . . . . . . . . . 5–85

RUN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–86

SELFTEST controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–89

SET controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–91

SET device-name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–102

SET EMU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–105

SET FAILEDSET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–108

SET FAILOVER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–110

SET mirrorset-name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–112

SET MULTIBUS_FAILOVER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–118

SET NOFAILOVER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–120

SET NOMULTIBUS_FAILOVER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–122

SET RAIDset-name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–124

SET unit-number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–128

SHOW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–136

SHUTDOWN controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–143

UNMIRROR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–145

Appendix A

System Profiles

Device Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A–2

Storageset Profile. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A–3

Enclosure Template . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A–4

Appendix B

Controller Specifications

Physical and Electrical Specifications for the Controller . . . . . . . . . . . . . . . . . . . B–2

Environmental Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B–3

Glossary Index

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

Figures

Basic Building Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–3

Bridging the Gap Between the Host and Its Storage Subsystem . . . . . . . . . . . . . . 1–7

HSZ80 Array Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–9

Parts Used in Configuring the HSZ80 Array Controller . . . . . . . . . . . . . . . . . . . 1–10

Optional Maintenance Port Cable for a Terminal Connection . . . . . . . . . . . . . . . 1–12

Location of Controllers and Cache Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–13

HSZ80 Controller Operator Control Panel (OCP) . . . . . . . . . . . . . . . . . . . . . . . . 1–14

Cache Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–19

ECB for Dual-Redundant Controller Configurations . . . . . . . . . . . . . . . . . . . . . . 1–30

Cabling for a Single-Controller Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–5

Cabling for a Dual-Redundant Controller Configuration in

Transparent Failover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–10

Cabling for a Dual-Redundant Controller Configuration in

Multiple-Bus Failover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–16

SCSI Target ID Numbers on the Controller Device Bus and PVA Settings in

an Extended Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–25

PC/Terminal to Maintenance Port Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–27

“This Controller” and “Other Controller” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–28

Host SCSI Bus and Controller Device Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–33

Units Created from Storagesets, Partitions, and Drives . . . . . . . . . . . . . . . . . . . . . 3–3

Storageset Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–6

Striping Lets Several Disk Drives Participate in Each I/O Request . . . . . . . . . . . . 3–9

Distribute Members across Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–11

Mirrorsets Maintain Two Copies of the Same Data . . . . . . . . . . . . . . . . . . . . . . . 3–13

First Mirrorset Members on Different Buses . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–14

Parity Ensures Availability; Striping Provides Good Read Performance . . . . . . . 3–16

Striping and Mirroring in the Same Storageset . . . . . . . . . . . . . . . . . . . . . . . . . . 3–18

CLONE Steps for Duplicating Unit Members . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–21

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Storageset Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–35

PTL Naming Convention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–37

PTL Addressing in an Extended Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . 3–38

Locating Devices using PTLs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–39

Partitioning a Single-Disk Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–40

Chunk Size Larger than the Request Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–52

Chunk Size Smaller than the Request Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–53

Setting Host Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4–25

Accessing Units on a Given Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4–27

Accessing Units with the Host Port’s SCSI ID Number . . . . . . . . . . . . . . . . . . . . 4–29

Accessing Units through Port Access and the Host Port’s SC SI ID Number . . . 4–31

Assigning Units through Multiple Host Adapters . . . . . . . . . . . . . . . . . . . . . . . . 4–33

Moving a Storageset from one Subsystem to Another . . . . . . . . . . . . . . . . . . . . . 4–35

Tables

Basic Building Blocks List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–4

Summary of Controller Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–5

HSZ80 Array Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–9

Description of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–10

Parts of the Optional Maintenance Port Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–12

Cache Module Memory Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–18

Location of Cache Module Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–19

Cache Policies and Cache Module Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–23

Resulting Cache Policies and ECB Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–25

ECB Capacity Based on Memory Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–29

Location of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–30

Location of Parts for a Single Controller Configuration . . . . . . . . . . . . . . . . . . . 2–5

Location of Parts for Transparent Failover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–11

Location of Parts for Multiple-Bus Failover . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–17

Controller Limitations for RAIDsets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–3

A Comparison of Different Kinds of Storagesets . . . . . . . . . . . . . . . . . . . . . . . . . . 3–8

Unit Numbering Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–33

Maximum Chunk Sizes for a RAIDset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–54

UNIT Switches for Storagesets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3–58

Recall and Edit Command Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–4

Unit Numbering Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–5

ADD UNIT Switches for Storagesets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–28

Poweroff Switch Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–75

SET controller Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–91

Maximum SCSI-Bus Lengths for Given Data Transfer Rate . . . . . . . . . . . . . . . 5–100

EMU Set Point Temperatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–106

SET UNIT Switches for Existing Containers . . . . . . . . . . . . . . . . . . . . . . . . . . . 5–129

Controller Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B–2

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Optimum Operating Environmental Specifications . . . . . . . . . . . . . . . . . . . . . . . .B–3

Maximum Operating Environmental Specifications . . . . . . . . . . . . . . . . . . . . . . .B–4

Maximum Nonoperating Environmental Specifications . . . . . . . . . . . . . . . . . . . .B–4

About This Guide

This book describes the features of the HSZ80 Array Controller, configuration procedures for the controller and storagesets running Array Controller Software (ACS) 8.3Z, and the CLI commands used in configuring.

This book does not contain information about the operating environments to which the controller may be connected, nor does it contain detailed information about subsystem enclosures or their components. See the documentation that accompanied those peripherals for information about them.

Getting Help

If you have a pro blem and ha ve exhaus ted the in formation i n this referen ce guide, you can get further information and other help in the following locations.

Compaq Website

The Compaq Website has information on this product as well as the latest drivers and Flash ROM images. You can access the Compaq website by logging on to the Internet at http://www.compaq.com.

Te lephone Numbers

For Compaq technical support: In the United States and Canada, call 1-800-652-6672. For Compaq technical support phone numbers outside the United States and Canada,

visit the Compaq Website at: http://www.compaq.com.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

xvi About This Guide

Precautions

Follow these precautions when you’re carrying out the procedures in this book.

Electrostatic Discharge Precautions

Static electricity collects on all nonconducting material, such as paper, cloth, and plastic. An electrostatic discharge (ESD) can easily damage a controller or other subsystem component even though you may not see or feel the discharge. Follow these precautions whenever you’re servicing a subsystem or one of its components:

■ Always use an ESD wrist strap when servicing the controller or other

components in the subsystem. Make sure that the strap contacts bare skin and fits snugly, and that its grounding lead is attached to a bus that is a verified earth ground.

■ Before touching any circuit board or component, always touch a verifiable earth

ground to discharge any static electricity that may be present in your clothing.

■ Always keep circuit boards and components away from nonconducting material.

■ Always keep clothing away from circuit boards and components.

■ Always use antistatic bags and grounding mats for storing circuit boards or

components during replacement procedures.

■ Always keep the ESD cover over the program card when the card is in the

controller. If you remov e the card, put it in its original carrying case. Never touch the contacts or twist or bend the card while you’re handling it.

■ Do not touch the connector pins of a cable when it is attached to a component or

host.

Component Precaution

System components referenced in this manual comply to regulatory standards documented herein. Use of other components in their place may violate country standards, negate regulatory compliance, or invalidate the warranty on your product.

VHDCI Cable Precautions

All of the cables to the controller, cache module, and external cache battery use veryhigh-density cable interconnect connectors (VHDCI). These connectors have extraordinarily small mating surfaces that can be adversely affected by dust and movement.

Use the following precautions when you’re connecting cables that use VHDCI connectors:

■ Clean the mating surfaces with a blast of clean air.

■ Mate the connectors by hand, then tighten the retaining screws to 1.5 inch-

pounds—approximately 1/4 additional turn after the connectors have fully mated.

■ Test the assembly by gently pulling on the cable, which should not produce

visible separation.

Maintenance Port Precautions

The maintenance port generates, uses, and radiates radio-frequency energy through cables that are connected to it. This energy may interfere with radio and television reception. Do not leav e a cable connected to this po rt when you’re not communicating with the controller.

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Conventions

This book uses the following typographical conventions and special notices to help

you find what you’re looking for.

Typographical Conventions

Convention Meaning

ALLCAPS Command syntax that must be entered exactly as shown

and for commands discussed within text, for example:

SET FAILOVER COPY=OTHER_CONTROLLER

“Use the SHOW SPARESET command to show the contents of the spareset.”

Monospaced Screen display.

Sans serif italic

italic Reference to other books, for example: “See

. . .

“this controller” The controller serving your current CLI session through a

“other controller” The controller in a dual-redundant pair that’s connected

Command variable or numeric value that you supply, for example:

SHOW

RAIDset-name

set this_controller id=

details.”

Indicates that a portion of an example or figure has been omitted.

local or remote terminal.

to the controller serving your current CLI session.

(n,n,n,n,)

....

for

Special Notices

This book doesn’t contain detailed descriptions of standard safety procedures. Howev er , it does contain warnings for proced ures that could cause personal injury and cautions for procedures that could damage the controller or its related components. Look for these symbols when you’re carrying out the procedures in this book:

xix

WARNING: A warning indicates the presence of a hazard that can cause

personal injury if you do not observe the precautions in the text.

CAUTION: A caution indicates the presence of a hazard that might damage hardware, corrupt software, or cause a loss of data.

IMPORTANT: An essential to the completion of a task. Users can disregard information in a note and still complete a task, but they should not disregard an important note.

NOTE: A note provides additional information that’s related to the completion of an instruction or procedure.

important

note is a type of note that provides information

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

xx About This Guide

Required Tools

You’ll need the following tools to service the controller, cache module, external cache battery (ECB), the Power Verification and Addressing (PVA) module and the I/O module:

■ A flathead screwdriver for loosening and tightening the I/O module retaining

screws.

■ A small phillips screwdriver for loosening and tightening the GLM access door

screws.

■ An antistatic wrist strap.

■ An antistatic mat on which to place modules during servicing.

■ A Storage Building Block (SBB) Extractor for removing StorageWorks building

blocks. This tool is not required, but it will enable you to perform more efficiently.

Related Publications

The following table lists some of the Compaq StorageWorks documents related to the use of the controller, cache module, external cache battery, graphical user interface, and the subsystem.

Document Title Part Number

BA370 Enclosure Rack Template (Compaq 42U Rack) 355224-001 EK-RKTMP-TP

Command Console Version 2.1 HSZ80 User’s Guide 388725-001 AA-RF9TA-TE Disaster Tolerant Solutions Getting Started Guide for DIGITAL UNIX Disaster Tolerant Solutions User’s Guide for DIGITAL UNIX External Cache Battery Shelf Installation Card (Compaq 42U Rack) Hardware Configuration Poster for HSZ80 388724-001 EK-HSZ80-CP HSZ80 Array Controller ACS V8.3 for DIGITAL UNIX CD-ROM HSZ80 Array Controller ACS V8.3 for DIGITIAL UNIX Release Notes HSZ80 Array Controller ACS V8.3 for IBM-AIX Release Notes HSZ80 Array Controller ACS V8.3 for OpenVMS Release Notes HSZ80 Array Controller ACS V8.3 Maintenance and Service Guide HSZ80 Array Controller Illustrated Parts Map 388220-001 EK-HSZ80-MP Installation Card (Compaq 42U Rack) 355210-001 EK-H80RM-IC Installing a Ferrite Bead on a Host Bus N/A EK-SWXES-IG The RAIDBOOK—A Source for RAID Technology N/A RAID Advisory Board RA8000/ESA12000 HSZ80 ACS V8.3 for DIGITAL UNIX Installation Reference Manual

N/A AA-RC3CA-TE

N/A EK-SWXDT-OP

355222-001 EK-HSECB-IC

N/A AG-RFA0A-BE

388713-001 AA-RF9YA-TE

388711-001 AA-RFALA-TE

388712-001 AA-RFAEA-TE

388221-001 EK-HSZ80-SV

388701-001 AA-RF9ZA-TE

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xxii About This Guide

Document Title Part Number

RA8000/ESA12000 HSZ80 ACS V8.3 for DIGITAL UNIX Quick Setup Guide RA8000/ESA12000 HSZ80 ACS V8.3 for IBM-AIX Installation Reference Manual RA8000/ESA12000 HSZ80 ACS V8.3 for IBM-AIX Quick Setup Guide RA8000/ESA12000 HSZ80 ACS V8.3 for OpenVMS Installation Reference Manual RA8000/ESA12000 HSZ80 ACS V8.3 for OpenVMS Quick Setup Guide

RA8000/ESA12000 Storage Subsystem User’s Guide 387404-001 EK-SMCPR-UG Rail Mounting Installation Card (Compaq 42U Rack) 355223-001 EK-H8RMB-IC Ultra SCSI RAID Enclosure (DS-BA370 Series) User’s Guide Warranty Terms and Conditions N/A EK-HSXSW-WC

388700-001 AA-RF9XA-TE

388710-001 AA-RFAMA-TE

388709-001 AA-RFAKA-TE

388733-001 AA-RFAFA-TE

388732-001 AA-RFADA-TE

387403-001 EK-BA370-UG

Revision History

This is a new document.

Chapter 1 General Description

This chapter illustrates and describes in general terms your subsystem an d its major components: the HSZ80 Array Controller, its cache module, and its external cache battery (E CB).

1–1

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

1–2 General Description

Typical Installation

Figure shows the major components, or basic building blocks, of the storage subsystem that is comprised of the following:

■ One BA370 rack-mountable enclosure.

■ Two controllers, each supported by a cache module.

■ Two External Cache Batteries (ECBs) in one Storage Building Block (SBB),

which provide backup power to the cache modules during a primary power failure.

■ One environmental monitoring unit (EMU) that monitors the subsystem’s

environment and alerts the controller of equipment failures that could cause an abnormal environment.

■ One Power Verification and Addressing (PVA) module that provides a unique

address to each enclosure in an extended subsystem.

■ Six I/O modules that integrate the SBB shelf with either an 8-bit single-ended,

16-bit single-ended, or 16-bit differential SCSI bus

■ Two cache modules, which support nonvolatile memory and dynamic cache

policies to protect the availability of its unwritten (write-back) data

1–3

Figure 1–1. Basic Building Block

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

CXO6742A

1–4 General Description

Item Description

1 BA370 rack-mountable enclosure 2 Cooling fan 3 Power cable kit 4 I/O module 5 SCSI hub, 3 port 6 SCSI hub, 5 port 7 SCSI hub, 9 port, upgrade 8 Cache module

9 HSZ80 controller 10 PVA module 11 EMU 12 AC input module 13 180-watt power supply 14 Disk drive, 4 GB, 7200

15 Power cable 16 ECB, dual (shown)

Table 1–1 Basic Building Blocks List

Disk drive, 9 GB, 7200 Disk drive, 18 GB, 7200 Disk drive, 9 GB, 10K Disk drive, 18 GB, 10K

ECB, single (not shown)

Summary of HSZ80 Features

Table 1–2 summarizes the features of the controller:

Table 1–2 Summary of Controller Features

Feature Supported Topology Dual host port Ultra SCSI Host protocol SCSI-2, Limited SCSI-3 Host bus interconnect Wide Ultra SCSI, Differential Number of host ports 2 on Wide Ultra SCSI, Differential Device protocol SCSI-2 Device bus interconnect Wide Ultra SCSI, Single-ended Number of SCSI device ports (or I/O modules) 6 Wide Ultra SCSI, Single-ended Number of SCSI device targets per port 12 Maximum number of SCSI target devices 72 Ultra SCSI disks RAID levels supported 0, 1, 0+1, 3/5 Cache module memory sizes supported 64 MB, 128 MB, 256 MB, 512 MB Maximum cache module size 512 MB PCMCIA program card software upgrades Yes Device warm swap Yes Exercisers available for testing disks Yes Maximum number of RAID-5 storagesets 20 Maximum number of RAID-5 and RAID-1 storagesets 30 Maximum number of RAID-5, RAID-1, and RAID-0

storagesets Maximum number of units presented to the host 128 Maximum number of partitions per storageset 8 Maximum members per mirrorset 6 Maximum number of members per RAID-5 storageset 14

1–5

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

1–6 General Description

Maximum number of members in a stripeset 24 Maximum number of physical devices in a striped

mirrorset Maximum host port transfer speed 20 MHz Largest device, storageset, or unit size 512 GB

Table 1–2 Summary of Controller Features (Continued)

Feature Supported

The HSZ80 Array Controller

Your controller is the intelligent bridge between your host and the devices in your subsystem.

1–7

Host

Controller

Figure 1–2. Bridging the Gap Between the Host and Its Storage Subsystem

Storage subsystem

CXO5505A

The controller shown in Figure 1–2 is an integral part of any storage subsystem because it provides a host with high-performance and high-availability access to storage devices. See the HSZ80 Array Controller ACS Version 8.3 Release Notes for the most recent list of supported devices and operating systems.

The controller provides the ability to com bin e several ordinary d isk drives into a single, high-performance storage unit called a storageset. Storagesets are implementations of RAID technology, which ensures that every unpartitioned storageset, whether it uses two disk drives or ten, looks like a single storage unit to the host. See Chapter 3 and Chapter 4 for more information about storagesets and how to configure them.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

1–8 General Description

From the host’s perspective, the controller is simply another device connected to one of its I/O buses. Consequently, the host sends its I/O requests to the controller just as it would to any SCSI device. From the subsystem’s perspective, the controller receives the I/O requests and directs them to the devices in the subsystem. Because the controller processes the I/O requests, the host isn’t burdened by the processing that’s typically associated with reading and writing data to multiple storage devices.

Figure 1–3 shows an HSZ80 Array Controller. Figure 1 –4 shows the parts used in configuring it and Table 1–4 lists the descriptions and part numbers.

NOTE: The maintenance port cable shipped with the controller has a 9-pin connector for a PC connection only. If you are using a terminal instead of a PC or if you have a system with a DB25 connection, you can obtain a cable as shown in

Figure 1–5 on page 1–12 from the local field service office.

To determine which parts you need for your configuration, you must have an idea of the type of configuration you will be running in y ou r subsystem. See the following sections for your configuration type:

■ “Configuring a Single Controller,” page 2–5

■ “Configuring Dual-Redundant Controllers in Transparent Failover Mode,”

page 2–10

■ “Configuring Dual-Redundant Controllers in Multiple-Bus Failover Mode,”

page 2–16

The components that you’ll use most often are conveniently located on the controller’s front panel, such as the maintenance port and the operator control panel (OCP). The host port and program-card slot are also located on the front panel, making it easy to update the controller’s software or to connect the controller to a different host.

1–9

1 2 3 4 5 6

Figure 1–3. HSZ80 Array Controller

Table 1–3 HSZ80 Array Controller

Item Description

➀ ➁ ➂ ➃ ➄ ➅ ➆ ➇

Backplane connector Host port 1 Host port 2 Program card slot Program card ejection button Release lever Maintenance port Operator Control panel

CXO6284B

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

1–10 General Description

1 2 3 4 5 6

Figure 1–4. Parts Used in Configuring the HSZ80 Array Controller

CXO6492B

Table 1–4 Description of Parts

Item Description

➀ ➁ ➂ ➃ ➄ ➅

Host port 1 Host port 2 ESD/PCMCIA program card ESD/PCMCIA program card cover Trilink connectors Host bus cable

Table 1–4 Description of Parts (Continued)

Item Description

➆ ➇ ➈ ➉

Ferrite bead Terminator Jumper cable Maintenance port cable

1–11

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

1–12 General Description

Figure 1–5. Optional Maintenance Port Cable for a Terminal Connection

Item Description

➀ ➁ ➂ ➃ ➄

CXO6505B

Table 1–5 Parts of the Optional Maintenance Port Cable

Cable assembly Ferrite bead RJ-11 Adapter RJ-11 Extension Cable PC Serial Port Adapter

Each controller is supported b y its own cache module. Figure 1–6 shows which cache module supports which controller in a dual-redundant controller configuration in a BA370 rack-mountable enclosure.

1–13

EMU

Controller A Controller B

Cache module A Cache module B

Figure 1–6. Location of Controllers and Cache Modules

IMPORTANT: Compaq recommends that you use the slots for controller A and cache module A for single controller configurations. Slot A responds to SCSI target ID number 7 on the device buses and slot B responds to SCSI target ID number 6 on the device buses.

Operator Control Panel

The operator control panel (OCP ) co nt ains a res et button and six port button LEDs as

shown in Figure 1–7. The reset button flashes about once per second to indicate that the controller is operating normally. The port button LEDs correspond to the controller’s device ports and remain off during normal operation. If an error occurs, the reset button and LEDs will illuminate in a solid or flashing pattern to help you diagnose the problem.

PVA

CXO6283A

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1–14 General Description

Reset button/ LED

123456

Figure 1–7. HSZ80 Controller Operator Control Panel (OCP)

Port button/ LED

CXO6216A

See Figure 1–3 on page 1–9 for the location of the OCP on the HSZ80 Array Controller.

Under normal circumstances, you will not need to remove the controller from its enclosure. For this reason, the components that you will use most often are conveniently located on the front panel. For example, the maintenance port pro vides a convenient way to connect a PC or term inal to yo ur con troller so that you can inter act with it.

After you conf igure you r contro ller , you shou ld period ically ch eck its co ntrol pan el. If an error occurs, one or more of the LEDs on the control panel will flash in a pattern that will help you to diagnose the problem. See the HSZ80 Array Controller ACS Version 8.3 Maintenance and Service Guid e for details about troubleshooting yo ur controller.

Maintenance Port

You can access the controller in two ways: through a PC or terminal via the maintenance port or through a remote terminal—sometimes called a virtual terminal or host console—via the host. Compaq recommends that you use a PC or terminal to carry out the troubleshooting and se rvicing procedures in this manual. See “Establishing a Local Conn ection to t he Controll er ,” page 2–26, for more information about connecting the controller with a maintenance port cable.

Utilities and Exercisers

The controller’s software includes the following utilities and exercisers to assist in troubleshooting and maintaining the controller and the other modules that support its operation. For more details on each of the utilities and exercisers, see the HSZ80 Array Controller ACS Version 8.3 Maintenance and Service Guide.

Fault Management Utility

The Fault Management Utility (FMU) provides a limited interface to the controller’s fault management system. As a troubleshooting tool, you can use FMU to:

■ Display the last-failure and memory-system-failure entries that the fault

management software stores in the controller’s nonvolatile memory.

■ Translate many of the event messages that are contained in the entries related to

the significant events and failures. For example, entries may contain codes that indicate the cause of the event, the software component that reported the event, the repair action, and so on.

■ Set the display characteristics of spontaneous events and failures that the fault

management system sends to the PC or terminal, or to the host.

1–15

Virtual Terminal Display

Use the virtual terminal display (VTDPY) utility to aid in troubleshooting the following issues:

■ Communication between the controller and its hosts.

■ Communication between the controller and the devices in the subsystem.

■ The state and I/O activity of the logical units, devices, and device ports in the

subsystem.

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Disk Inline Exerciser

Use the disk inline exerciser (DILX) to investigate the data-transfer capabilities of

disk drives. DILX tests and verifies operation of the controller and the SCSI–2 disk drives attached to it. DILX generates intense read and write loads to the disk drive while monitoring the drive’s performance and status.

Configuration Utility

Use the configuration (CONFIG) utility to add one or more storage devices to the subsystem. This utility checks the device ports for new disk drives, then adds them to the controller’s configuration and automatically names them.

HSUTIL

Use HSUTIL to upgrade the firmware on disk drives in the subsystem and to format disk drives.

Code Load and Code Patch Utility

Use the Code Load/Code Patch (CLCP) utility to upgrade the controller software and the EMU software. You can also use it to patch the controller software. Whenever you install a new controller , you must hav e the correct software v ersion and patch number.

IMPORTANT: Only Compaq field service personnel are authorized to upload EMU microcode updates. Contact the Customer Service Center (CSC) for directions in obtaining the appropriate EMU microcode and installation guide.

Clone Utility

Use the Clone utility to duplicate the data on any unpartitioned mirrorset. Back up the cloned data while the actual storageset remains online.

1–17

Field Replacement Utility

Use the field replacement utility (FRUTIL) to replace a failed controller (in a dualredundant configuration) without shutting down the subsystem.You can also use this menu-driven utility to replace cache modules, external cache batteries, and the PVA module.

Change Volume Serial Number Utility

Only Compaq authorized service personnel may use th is utility. The Change Volume Serial Number (CHVSN) utility generates a new volume serial

number (called VSN) for the specified device and writes it on the media. It is a w ay to eliminate duplicate volume serial numbers and to rename duplicates with different volume serial numbers.

Device Statistics Utility

The Device Statistics (DSTAT) utility allows you to log I/O activity on a controller over an extended period of time. Later, you can analyze that log to determine where the bottlenecks are and how to tune the controller for optimum performance.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

1–18 General Description

Cache Module

Each controller requires a companion cache module as shown in Figure 1–8. Table 1–7 lists the descriptions and part numbers of the cache module. Figure 1–6 on page 1–13 shows the location of a controller’s companion cache module.

The cache module, which contains up to 512 MB of memory, increases the subsystem’s I/O performance by providing read, read-ahead, write-through, and write-back caching. The size of the memory contained in the cache module depends on the configuration of the DIMMs, with the support e d combinations shown in Table 1–6. For placement of the DIMMs, see the HSZ80 Array Controller ACS Version 8.3 Maintenance and Service Guid e.

32 MB 2 64 MB 32 MB 4 128 MB 128 MB 2 256 MB 128 MB 4 512 MB

Table 1–6 Cache Module Memory Configurations

DIMMs Quantity Memory

Figure 1–8. Cache Module

Item Description

1–19

CXO6306B

Table 1–7 Location of Cache Module Parts

➀ ➁ ➂ ➃ ➄

Cache memory power LED ECB Y cable Release lever Backplane connector DIMM

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

1–20 General Description

Caching Techniques

The cache module supports the following caching techniques to increase the

subsystem’s read and write performance:

■ Read caching

■ Read-ahead caching

■ Write-through caching

■ Write-back caching

Read Caching

When the controller receives a read request from the host, it reads the data from the disk drives, delivers it to the host, and also stores the data in its cache module. This process is called read caching.

Read caching can decrease the subsystem’s response time to many of the host’s read requests. If the host requests some or all of the cached data, the controller satisf ies the request from its cache module rather than from the disk drives. By default, read caching is enabled for all storage units.

To set the maximum cache that can be transferred, see “SET unit-number” in Chapter 5, “CLI Commands.”

Read-Ahead Caching

Read-ahead caching begins once the controller has already processed a read request and it receives a sequential read request from the host. If the controller does not find the data in the cache memory, it reads the data from the disks and sends it to the cache memory .

1–21

The controller then anticipates subsequent read requests and begins to prefetch the next blocks of data from the di sk s as it sends th e reques t ed read data to the ho st. Thi s is a parallel action. The controller notifies the host of the read completion, and subsequent sequential read requests are satisfied through the cache memory. By default, read-ahead caching is enabled for all disk units.

Write-Through Caching

When the controller receives a write request from the host, it stores the data in its cache module, writes the data to the disk drives, then notifies the host when the write operation is complete. This process is called write-through caching because the data

actually passes through—and is stored in—the cache memory on its way to the disk drives.

If you enable read caching for a storage unit, write-through caching is automatically enabled. Likewise, if you disable read caching, write-through caching is automatically disabled.

Write-Back Caching

This caching technique decreases the subsystem’s response time to write requests by allowing the controller to declare the write operation “complete” as soon as the data reaches its cache memory. The controller performs the slower operation of writing the data to the disk drives at a later time.

By default, write-back caching is enabled for all disk units. In either case, the controller will not provide write-back caching to a unit unless the cache memory is nonvolatile, as described in the next section.

If the mirrorset is a disaster-tolerant mirrorset, then write-back caching cannot be enabled.

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1–22 General Description

Fault-Tolerance for Write-Back Caching

The cache module supports nonvolatile memory and dynamic cache policies to protect the availability of its unwritten (write-back) data.

Nonvolatile Memory

Except for disaster-tolerant supported mirrorsets, the controller can provide write-

back caching for storage units as long as the controller’s cache memory is nonv olatile. In other words, to enable write-back caching, you must provide a backup power source to the cache module to preserve the unwritten cache data in the event of a power failure. If the cache memory were volatile—that is, if it didn’t have a backup power supply—the unwritten cache data would be lost during a power failure.

By default, the controller expects to use an ECB as the backup power source for its cache module. See “External Cache B attery,” page 1–29, for more information on the ECB.

However, if your subsy stem is backed up by an uninterruptible power supply (UPS), you can tell the controller to use the UPS as the backup power source with the command, SET Controller, and using the CACHE_UPS switch.

Cache Policies Resulting from Cache Module Failures

If the controller detects a full or partial failure of its cache module or ECB, it automatically reacts to preserve the unwritten data in its cache module. Depending upon the severi ty of the f ailur e, the co ntroller choo ses an interim cach ing techn ique— also called the cache policy—which it uses until you repair or replace the cache module.

Table 1–8 shows the cache policies resulting from a full or partial failure of cache module A in a dual-redundant controller configuration. The consequences shown in this table are the same for cache module B.

Table 1–9 shows the cache policies resulting from a full or partial failure of cache module A’s ECB in a dual-redundant controller configuration . When cache module A is at least 50% charged, the ECB is still good and is charging. When it is less than 50% charged, the ECB is low, but still charging. The consequences shown are the opposite for a failure of cache module B’s ECB.

Table 1–8 Cache Policies and Cache Module Status

Cache Module Status Cache Policy

Cache A Cache B Unmirrored Cache Mirrored Cache

1–23

Good Good Data loss: No.

Cache policy: Both controllers support write-back caching.

Failover: No.

Multibit cache memory failure

Good Data loss: Forced error and loss of

write-back data for which the multibit error occurred. Controller A detects and reports the lost blocks.

Cache policy: Both controllers support write-back caching.

Failover: No.

Data loss: No. Cache policy: Both controllers support

write-back caching. Failover: No.

Data loss: No. Controller A recovers its lost write-back data from the mirrored copy on cache B.

Cache policy: Both controllers support write-back caching.

Failover: No.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

1–24 General Description

Table 1–8 Cache Policies and Cache Module Status (Continued)

Cache Module Status Cache Policy

Cache A Cache B Unmirrored Cache Mirrored Cache

DIMM or cache memory controller chip failure

Good Data integrity: Write-back data that

was not written to media when failure occurred was not recovered.

Cache policy: Controller A supports write-through caching only; controller B supports write-back caching.

Failover: In transparent failover, all units failover to controller B. In multiple-bus failover with hostassist, only those units that use write-back caching, such as RAIDsets and mirrorsets, failover to controller B. All units with lost data become inoperative until you clear them with the CLEAR LOST_DATA

command. Units that didn’t lose data operate normally on controller B.

In single controller configurations, RAIDsets, mirrorsets, and all units with lost data become inoperative. Although you can clear the lost data errors on some units, RAIDsets and mirrorsets remain inoperative until you repair or replace the nonvolatile memory on cache A.

Data integrity: Controller A recovers all of its write-back data from the mirrored copy on cache B.

Cache policy: Controller A supports write-through caching only; controller B supports write-back caching.

Failover: In transparent failover, all units failover to controller B and operate normally. In multiple-bus failover with host-assist, only those units that use write-back caching, such as RAIDsets and mirrorsets, failover to controller B.

Table 1–8 Cache Policies and Cache Module Status (Continued)

Cache Module Status Cache Policy

Cache A Cache B Unmirrored Cache Mirrored Cache

1–25

Cache Board Failure

Good Same as for DIMM failure. Data integrity: Controller A recovers all

of its write-back data from the mirrored copy on cache B.

Cache policy: Both controllers support write-through caching only. Controller B cannot execute mirrored writes because cache module A cannot

mirror controller B’s unwritten data. Failover: No.

Table 1–9 Resulting Cache Policies and ECB Status

Cache Module Status Cache Policy

Cache A Cache B Unmirrored Cache Mirrored Cache

At least 50% charged

Data loss: No. Cache policy: Both controllers

continue to support write-back caching.

Failover: No.

Data loss: No. Cache policy: Both controllers continue

to support write-back caching. Failover: No.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

1–26 General Description

Table 1–9 Resulting Cache Policies and ECB Status (Continued)

Cache Module Status Cache Policy

Cache A Cache B Unmirrored Cache Mirrored Cache

Less than 50% charged

At least 50% charged

Data loss: No. Cache policy: Controller A supports

write-through caching only; controller B supports write-back caching.

Failover: In transparent failover, all units failover to controller B.

In multiple-bus failover with hostassist, only those units that use write-back caching, such as RAIDsets and mirrorsets, failover to controller B.

In single-controller configurations, the controller only provides writethrough caching to its units.

Data loss: No. Cache policy: Both controllers continue

to support write-back caching. Failover: No.

Table 1–9 Resulting Cache Policies and ECB Status (Continued)

Cache Module Status Cache Policy

Cache A Cache B Unmirrored Cache Mirrored Cache

1–27

Failed At least

50% charged

Less than 50% charged

Data loss: No. Cache policy: Controller A supports

write-through caching only; controller B supports write-back caching.

Failover: In transparent failover, all units failover to controller B and operate normally.

In multiple-bus failover with hostassist, only those units that use write-back caching, such as RAIDsets and mirrorsets, failover to controller B.

In single-controller configurations, the controller only provides writethrough caching to its units.

Data loss: No. Cache policy: Both controllers

support write-through caching only. Failover: No.

Data loss: No. Cache policy: Both controllers continue

to support write-back caching. Failover: No.

Data loss: No. Cache policy: Both controllers support

write-through caching only. Failover: No.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

1–28 General Description

Table 1–9 Resulting Cache Policies and ECB Status (Continued)

Cache Module Status Cache Policy

Cache A Cache B Unmirrored Cache Mirrored Cache

Failed Less than

50% charged

Failed Failed Data loss: No.

Data loss: No. Cache policy: Both controllers

support write-through caching only. Failover: In transparent failover, all

units failover to controller B and operate normally.

In multiple-bus failover with hostassist, only those units that use write-back caching, such as RAIDsets and mirrorsets, failover to controller B.

In single-controller configurations, the controller only provides writethrough caching to its units.

Cache policy: Both controllers support write-through caching only.

Failover: No. RAIDsets and mirrorsets become inoperative. Other units that use write-back caching operate with write-through caching only.

Data loss: No. Cache policy: Both controllers support

write-through caching only. Failover: No.

Data loss: No. Cache policy: Both controllers support

write-through caching only. Failover: No. RAIDsets and mirrorsets

become inoperative. Other units that use write-back caching operate with write-through caching only.

External Cache Battery

To preserve the write-back cache data in the event of a primary power failure, a cache module must be connected to an ECB or a UPS.

Compaq supplies two versions of ECBs: a single-battery ECB for single controller configurations, and a dual-battery ECB for dual-redundant controller configurations,

which is shown in Figure 1–9. When the batteries are fully charged, an ECB can preserve 512 MB of cache memory for 24 hours. However, the battery capacity depends upon the size of memory contained in the cache module, which are listed in Table 1–10.

Table 1–10 ECB Capacity Based on Memory Size

Size DIMM Combinations Capacity 64 MB Two, 32 MB each 96 hours 128 MB Four, 32 MB each 48 hours 256 MB Two, 128 MB each 48 hours 512 MB Four, 128 MB each 24 hours

1–29

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

1–30 General Description

Figure 1–9. ECB for Dual-Redundant Controller Configurations

CACHE POWER

STATUS SHUT OFF

SHUT OFF STATUS

POWER CACHE

CXO6305B

Table 1–11 Location of Parts

Item Description

➀ ➁ ➂ ➃

Shut off button Status LED ECB Y cable Male port

Charging Diagnostics

Whenever you restart the controller, its diagnostic routines automatically check the

charge in the ECB’s batteries. If the batteries are fully charged, the controller reports them as fully charged and recheck s them every 24 hour s. If the b atteries are ch arging, the controller rechecks them every 4 minutes. Batteries are reported as being either above or below 50 percent in capacity. Batteries below 50 percent in capacity are also referred to as being low.

This 4-minute pollin g continues fo r up to 10 ho urs—the maximum time it shoul d take to recharge the batteries. If the batteries have not been charged sufficiently after 10 hours, the controller declares them to be failed.

Battery Hysteresis

When charging a battery, write-back caching will be allowed as long as a previous down time has not drained more than 50 percent of a battery’s capacity. When a battery is operating below 50 percent capacity, the battery is considered to be low and write-back caching is disabled.

CAUTION: Compaq recommends that you replace the ECB every two years to prevent battery failure.

1–31

IMPORTANT: If a UPS is used for backup power, the controller does not check the battery. To set the subsystem to use a UPS or to instruct the controller on per-

forming regular battery checks, see “SET controller” in Chapter 5, “CLI Commands.”

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

Chapter 2 Configuring an HSZ80 Array Controller

This chapter explains how to configure an HSZ80 Array Controller and the modules that support its operation in a StorageWorks subsystem.

2–1

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

2–2 Configuring an HSZ80 Array Controller

Introduction

Use the Quick Setup Guide that came with your subsystem to unpack and set up your subsystem prior to configuring your controller.

Unless you specifically requested a preconfigured subsystem, you will have to configure your controller and its subsystem before you can use them. Use the procedure in this chapter to configure your controller. The procedure contains references to more detailed information, should you need it.

For the complete syntax and descriptions of the CLI commands used in the

configuration procedure, see Chapter 5, “CLI Commands.”

Configuration Rules

Before you configure your controller, review these configuration rules and ensure your planned configuration meets the following requirements and conditions:

■ Maximum 15 targets with up to 32 LUNs on each target, depending on the

operating system

❏ Maximum 128 assignable, host-visible LUNs acros s all 15 targets

■ Maximum 512-GB LUN capacity

■ Maximum 72 physical devices

■ Maximum 20 RAID-5 storagesets

■ Maximum 30 RAID-5 and RAID-1 storagesets

■ Maximum 45 RAID-5, RAID-1, and RAID-0 storagesets

■ Maximum 8 partitions per storages et or individual disk

■ Maximum 6 members per mirrorset

■ Maximum 14 members per RAID-5 storageset

■ Maximum 24 members per stripeset

■ Maximum 48 physical devices per striped mirrorset

Configuring an HSZ80 Array Controller

You can use this procedure to configure yo ur controller i n one of three conf ig urations:

1) single controller, 2) dual controllers in transparent failover mode, or 3) dual controllers in multiple-bus failover (host-assisted) mode. When you are done configuring the controller, you can then add devices, plan storagesets, and configure storagesets. These tasks can be performed either with SWCC or using CLI co mmands from a PC or terminal.

See the following sections for your configuration type:

■ “Configuring a Single Controller,” page 2–5

■ “Configuring Dual-Redundant Controllers in Transparent Failover Mode,”

page 2–10

■ “Configuring Dual-Redundant Controllers in Multiple-Bus Failover Mode,”

page 2–16

A Few Tips

As you configure the controller, keep these points in mind:

■ Cabling—You can either configure the controller with a maintenance port cable

and no SCSI host bus cables connected to the h ost, or you can co nfigure with the SCSI host bus cables connected:

❏ SWCC—You can configure the controller using the SWCC graphical user

interface. See the Command Co ns ol e for HSZ 80 Sol u tio ns Gett ing Started Guide for more details.

❏ CLI Commands—You can configure the controller with CLI commands

using a terminal program.

2–3

NOTE: Eventually, you must connect the SCSI host bus cables between the controllers and the host. You can connect the SCSI host bus cables after configuring the controllers using a maintenance port cable.

■ EMU Alarm Control Switch—If the EMU alarm goes off, simply press it to stop

it. Check the error message to verify the type of error condition.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

2–4 Configuring an HSZ80 Array Controller

■ CLI Commands—A few commands can be used while configuring the controller: ❏ CLEAR_ERRORS CLI—Clears all error messages so you can type without the

messages being repeated. Make sure you read each error m essage before deleting it.

❏ SHOW THIS_CONTROLLER FULL and SHOW OTHER_CONTROLLER FULL—Lists

the full information about the controller.

Configuring a Single Controller

1 2 3 4 5 6

2–5

Figure 2–1. Cabling for a Single-Controller Configuration

Table 2–1 Location of Parts for a Single Controller Configuration

Item Description

➀ ➁ ➂ ➃ ➄ ➅

Host port 1 Host port 2 Trilink connector Host bus cable Ferrite bead Terminator

CXO6285B

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

2–6 Configuring an HSZ80 Array Controller

Follow these steps to configure a controller:

NOTE: This procedure has been written for first-time configuring. However, you can adapt the procedure when you reconfigure the controllers. For replacing and upgrading the controllers, see the

Maintenance and Service Guide

1. Use the power-verificati on and addressing (PVA) module ID switch to set the SCSI ID number for the BA370 rack-mountable enclosure.

See “Setting the PVA Module ID Switch,” page 2–25, for details about PVA switch settings.

2. Remove the program card ESD cover, and insert the program card into the controller. Replace the ESD cover.

3. Turn on the power to the enclosure or cabinet by turning on the ac input boxes.

4. Establish a local connection to the controller.

See “Establishing a Local Connection to the Controller,” page 2–26, for details about creating a local connection.

5. Set the SCSI target ID numbers for the controller. Use the following commands:

SET THIS_CONTROLLER PORT_1_ID = (

HSZ80 Array Controller ACS Version 8.3

n,n

)

n,n

SET THIS_CONTROLLER PORT_2_ID = (

See “Setting SCSI Target ID Numbers,” page 2–33, for details about val id SCSI tar get ID numbers.

)

2–7

6. Set the host function mode for the controller using the target ID numbers set in step 5. Use the following command:

NOTE: The default host function mode defaults to Host Mode A. The HOST_FUNCTION switch changes the host function mode to a different mode.

SET THIS_CONTROLLER HOST_FUNCTION= (

ID, MODE

)

To change the host function mode, see “SET controller,” page 5–91 for information on the HOST_FUNCTION switch.

7. Restart the controller using the following command:

RESTART THIS_CONTROLLER

See “RESTART controller” in Chapter 5, “CLI Commands.”

8. Set the time on the controller, which provides a baseline for replacing the external battery, using the following command:

SET THIS_CONTROLLER TIME=DD-MMM-YYYY:HH:MM:SS

NOTE: All values are numbers, except for MMM, which uses the first three letters of the month. When setting hours, minutes, and seconds—HH, MM, and SS—you must use 24-hour time.

9. Set up the battery discharge timer: a. Start Fru til using the following command:

RUN FRUTIL

Frutil displays the following:

Do you intend to replace this controller’s cache battery? Y/N

b. Enter Y(es). Frutil displays a three-step procedure and prompts you to press return. c. Press return.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

2–8 Configuring an HSZ80 Array Controller

10. Enter any other optional CLI commands for your configuration.

See “Optional Steps,” page 2–22 and Chapter 5, “CLI Commands.”

11. Display details about the controller you configured. Use the following command:

SHOW THIS_CONTROLLER FULL

See “SHOW” in Chapter 5, “CLI Commands.”

IMPORTANT: If you are using a PC or terminal with the maintenance port cable,

you must connect the SCSI bus cables in the desired configuration. See “Connecting a Single Controller to the Host,” page 2–9,for more information about configurations.

Connecting a Single Controller to the Host

Follow these steps and Figure 2–1 to connect a single, nonredundant controller to the host:

1. Configure the controller. See “Configuring a Single Controller,” page 2–5.

2. Ensure the host and adapter are also configured. See the host user’s guide for details.

3. Connect a trilink to the controller going into host Po rt 1: a. Co nnect the host bus cable onto one end of the trilink connector. b. For a BA370 enclosure residing in an SW600 cabinet, snap the ferrite bead

on the bus cable within one inch of the controller.

4. Connect a terminator on the trilink connector for host Port 1: a. If the controller is at the end of the host bus, connect a terminator to the other

connector on the front of the trilink connector.

b. Otherwise, connect a cable that continues to the next device on the bus. Be

sure to install a terminator at the end of the bus.

5. Repeat steps 3 and 4 for host Port 2.

2–9

IMPORTANT: The HSZ80 Array Controller has dual-host ports, Port 1 and Port 2,

which may be configured at the same time. The configuration in Figure 2–1 only shows a connection to host Port 1. However, you may also configure host Port 2 the same way, depending on your system requirements.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

2–10 Configuring an HSZ80 Array Controller

Configuring Dual-Redundant Controllers in Transparent Failover Mode

1 2 3 4 5 6

CXO6287B

Figure 2–2. Cabling for a Dual-Redundant Controller Configuration in Transparent Failover

Table 2–2 Location of Parts for Transparent Failover

Item Description

➀ ➁ ➂ ➃ ➄ ➅ ➆

Follow these steps to configure a controller:

NOTE: This procedure has been written for first-time configuring. However, you can adapt the procedure when you reconfigure the controllers. For replacing and upgrading the controllers, see the

Maintenance and Service Guide

1. Use the power-verification and addressing (PVA) module ID switch to set the SCSI ID number for the BA370 rack-mountable enclosure.

Host port 1 Host port 2 Trilink connector Host bus cable Ferrite bead Terminator Jumper cable

HSZ80 Array Controller ACS Version 8.3

2–11

See “Setting the PVA Module ID Switch,” page 2–25, for details about PVA switch settings.

2. Remove the program card ESD cover, and insert the program card into the controller. Replace the ESD cover. Repeat for the other controller.

3. Turn on the power to the enclosure or cabinet by turning on the ac input boxes.

4. Establish a local connection to the controllers.

See “Establishing a Local Connection to the Controller,” page 2–26, for details about creating a local connection.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

2–12 Configuring an HSZ80 Array Controller

5. Put this controller into transparent failover mode. Use the following command:

CAUTION: Issuing the SET FAILOVER COPY command will overwrite data on the companion controller. If you are reconfiguring the control-

lers, see “CONFIGURATION RESET” in Chapter 5, “CLI Commands,” before proceeding and for more information.

SET FAILOVER COPY = THIS_CONTROLLER

The other controller inherits this controller’s configuration, then restarts. Wait for it to return to normal operation before continuing.

See details about failover modes in “Selecting a Failover Mode,” page 2–29.

6. If you want to enable mirrored write-back cache in a failo v er conf igu ration, enter this command:

SET THIS_CONTROLLER MIRRORED_CACHE

NOTE: Both controllers restart when you set mirror mode. This process can take up to 5 minutes, depending on the amount of data that must be flushed from the cache.

For details about caching techniques, see “Caching Techniques,” page 1–20. For details about mirrored write-back cache, see “Enabling Mirrored Write-Back

Cache,” page 2–31.

7. Set the SCSI target ID numbers for the controller. Use the following command:

n,n

)

SET THIS_CONTROLLER PORT_1_ID= (

SET THIS_CONTROLLER PORT_2_ID= (

See “Setting SCSI Target ID Numbers,” page 2–33, for details about val id SCSI tar get ID numbers.

2–13

8. If you are configuring controllers in transparent f ailov er mod e, prefer some or all SCSI target ID numbers to the controllers. Use the following command:

n, n

SET THIS_CONTROLLER PORT_1_PREFERRED_ID = (

)

n,n

SET THIS_CONTROLLER PORT_2_PREFERRED_ID = (

)

where n,n is a subset of the target ID numbers you declared in step 5.

See “Using Preferred ID Numbers,” page 2–35, for details about preferred SCSI target ID numbers.

9. Set the host function mode for the controller using the target ID numbers set in step 7 and in step 8. Use the following command:

NOTE: The default host function mode defaults to Host Mode A. The HOST_FUNCTION switch changes the host function mode to a different mode.

SET THIS_CONTROLLER HOST_FUNCTION= (

ID, MODE

)

SET OTHER_CONTROLLER HOST_FUNCTION= (

ID, MODE

)

To change the host function mode, see “SET controller,” page 5–91 for information on the HOST_FUNCTION switch.

10. Restart the controllers using the following command:

NOTE: After restarting the other controller, the EMU alarm will sound. To stop it, restart this controller.

RESTART OTHER_CONTROLLER RESTART THIS_CONTROLLER

See “RESTART controller” in Chapter 5, “CLI Commands.”

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

2–14 Configuring an HSZ80 Array Controller

11. Set the time on the controller, which provides a baseline for replacing the external battery, using the following command:

SET THIS_CONTROLLER TIME=DD-MMM-YYYY:HH:MM:SS

NOTE: All values are numbers, except for MMM, which uses the first three

letters of the month. When setting hours, minutes, and seconds—HH, MM, and SS—you must use 24-hour time.

12. Set up the battery discharge timer: a. Start Fru til using the following command:

RUN FRUTIL

Frutil displays the following:

Do you intend to replace this controller’s cache battery? Y/N

b. Enter Y(es). Frutil displays a three-step procedure and prompts you to press return. c. Press return.

13. Enter any other optional CLI commands for your configuration.

See the following section, “Optional Steps,” and Chapter 5, “CLI Commands.”

14. Display details about the controller you configured. Use the following command:

SHOW THIS_CONTROLLER FULL

See “SHOW” in Chapter 5, “CLI Commands.”

IMPORTANT: If you are using a PC or terminal with the maintenance port cable,

you must connect the SCSI bus cables in the desired configuration. See “Connecting in Transparent Failover Mode to the Host,” page 2–15,for more information about configurations.

Connecting in Transparent Failover Mode to the Host

Use the following steps and Figure 2–2 t o connect a p air of du al-redundan t controlle rs to the host:

1. Configure both controllers. See “Configuring Dual-Redundant Controllers in Transparent Failover Mode,” page 2–10.

2. Ensure the host and adapter are also configured. See the host user’s guide for details.

3. Connect two trilink connectors between both controllers going into host Port 1 with a jumper cable:

a. Attach one end of the jumper cable to one trilink. b. Attach the other end of the jumper cable to the other trilink.

4. Connect the host bus cable onto one end of the trilink connector: a. For a BA370 enclosure residing in an SW600 cabinet, snap the ferrite bead

on the bus cable within one inch of the controller.

5. Connect a terminator on the end of the trilink connector for host Port 1: a. If the controller is at the end of the host bus, connect a terminator to the other

connector on the front of the trilink connector.

b. Otherwise, connect another host bus cable that continues to the next device

on the bus. Be sure to install a terminator at the end of the bus.

2–15

6. Repeat steps 3, 4, and 5 for host Port 2 on both controllers.

IMPORTANT: The HSZ80 Array Controller has dual-host ports, Port 1 and Port 2,

which may be configured at the same time. The configuration in Figure 2–2 only shows a connection to host Port 1. However, you may also configure host Port 2 the same way, depending on your system requirements.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

2–16 Configuring an HSZ80 Array Controller

Configuring Dual-Redundant Controllers in Multiple-Bus Failover Mode

1 2 3 4 5 6

CXO6286

Figure 2–3. Cabling for a Dual-Redundant Controller Configuration in Multiple-Bus Failover

Table 2–3 Location of Parts for Multiple-Bus Failover

Item Description

➀ ➁ ➂ ➃ ➄ ➅

Follow these steps to configure a controller:

NOTE: This procedure has been written for first-time configuring. However, you can adapt the procedure when you reconfigure the controllers. For replacing and upgrading the controllers, see the

Maintenance and Service Guide

1. Use the power-verification and addressing (PVA) module ID switch to set the SCSI ID number for the BA370 rack-mountable enclosure.

Host port 1 Host port 2 Trilink connector Host bus cable Ferrite bead Terminator

HSZ80 Array Controller ACS Version 8.3

2–17

See “Setting the PVA Module ID Switch,” page 2–25, for details about PVA switch settings.

2. Remove the program card ESD cover, and insert the program card into the controller. Replace the ESD cover. Repeat for the other controller.

3. Turn on the power to the enclosure or cabinet by turning on the ac input boxes.

4. Establish a local connection to the controllers.

See “Establishing a Local Connection to the Controller,” page 2–26, for details about creating a local connection.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

2–18 Configuring an HSZ80 Array Controller

5. Put this controller in multiple-bus failover mode, using the following command:

CAUTION: Issuing the SET MULTIBUS_FAILOVER COPY command will overwrite data on the companion controller. If you are reconfiguring the

controllers, see “CONFIGURATION RESET” in Chapter 5, “CLI Commands,” before proceeding and for more information.

SET MULTIBUS_FAILOVER COPY = THIS_CONTROLLER

The other controller inherits this controller’s configuration, then restarts. Wait for it to return to normal operation before continuing.

See “Selecting a Failover Mode,” page 2–29, for details about failover modes.

6. If you want to enable mirrored write-back cache in a failo v er conf igu ration, enter this command:

SET THIS_CONTROLLER MIRRORED_CACHE

NOTE: Both controllers restart when you set mirror mode. This process can take up to 5 minutes, depending on the amount of data that must be flushed from the cache.

For details about caching techniques, see “Caching Techniques,” page 1–20. For details about mirrored write-back cache, see “Enabling Mirrored Write-Back

Cache,” page 2–31.

7. Set the SCSI target ID numbers for the controller. Use the following command:

n,n

)

SET THIS_CONTROLLER PORT_1_ID= (

SET THIS_CONTROLLER PORT_2_ID= (

See “Setting SCSI Target ID Numbers,” page 2–33, for details about val id SCSI tar get ID numbers.

2–19

8. Set the host function mode for the controller using the target ID numbers set in step 7. Use the following command:

NOTE: The default host function mode defaults to Host Mode A. The HOST_FUNCTION switch changes the host function mode to a different mode.

SET THIS_CONTROLLER HOST_FUNCTION= (

ID, MODE

)

SET OTHER_CONTROLLER HOST_FUNCTION= (

ID, MODE

)

To change the host function mode, see “SET controller,” page 5–91 for information on the HOST_FUNCTION switch.

9. Restart the controllers using the fo llowing comm a nd:

NOTE: After restarting the other controller, the EMU alarm will sound. To stop it, restart this controller.

RESTART OTHER_CONTROLLER RESTART THIS_CONTROLLER

See “RESTART controller” in Chapter 5, “CLI Commands.”

10. Set the time on the controller, which provides a baseline for replacing the external battery, using the following command:

SET THIS_CONTROLLER TIME=DD-MMM-YYYY:HH:MM:SS

NOTE: All values are numbers, except for MMM, which uses the first three letters of the month. When setting hours, minutes, and seconds—HH, MM, and SS—you must use 24-hour time.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

2–20 Configuring an HSZ80 Array Controller

11. Set up the battery discharge timer: a. Start Fru til using the following command:

RUN FRUTIL

Frutil displays the following:

Do you intend to replace this controller’s cache battery? Y/N

b. Enter Y(es). Frutil displays a three-step procedure and prompts you to press return. c. Press return.

12. Enter any other optional CLI commands for your configuration.

See the following section, “Optional Steps,” and Chapter 5, “CLI Commands.”

13. Display details about the controller you configured. Use the following command:

SHOW THIS_CONTROLLER FULL

See “SHOW” in Chapter 5, “CLI Commands.”

IMPORTANT: If you are using a PC or terminal with the maintenance port cable,

you must connect the SCSI bus cables in the desired configuration. See “Connecting in Multiple-Bus Failover Mode to the Host,” page 2–21,for more information about configurations.

Connecting in Multiple-Bus Failover Mode to the Host

Use the following steps and Figure 2–3 to connect a pair of multiple-bus failover, dual-redundant controllers to the host:

1. Configure both controllers. See “Configuring Dual-Redundant Controllers in Multiple-Bus Failover Mode,” page 2–16.

2. Ensure the host and adapter are also configured. See the host user’s guide for details.

3. Connect a trilink connector on host Port 1 or host Port 2 for one controller: a. Connect the host bus cable onto one end of each trilink connector. b. For a BA370 enclosure residing in an SW600 cabinet, snap the ferrite bead

on the bus cable within one inch of the controller.

4. Connect another trilink connector on host Port 1 or host Port 2 for a second controller:

a. Con nect the hos t bus cable onto one end of each trilink connector. b. For a BA370 enclosure residing in an SW600 cabinet, snap the ferrite bead

on the bus cable within one inch of the controller.

2–21

5. Connect a terminator on the end of each trilink connector: a. If the controller is at the end of the host bus, connect a terminator to the other

connector on the front of the trilink connector.

b. Otherwise, connect another host bus cable that continues to the next device

on the bus. Be sure to install a terminator at the end of the bus.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

2–22 Configuring an HSZ80 Array Controller

6. Repeat steps 3, 4, and 5 for connecting a third and a fourth host bus.

IMPORTANT: The HSZ80 Array Controller has dual-host ports, Port 1 and Port 2,

which may be configured at the same time. The configuration in Figure 2–3 shows a two-bus connection going into host Port 1. However, you may also configure host Port 2 the same way, depending on your system requirements. For a two-bus connection, the bus connections can occur on either host port on two controllers. A third and fourth bus connection can also be made if three or four buses are desired.

Optional Steps

You can perform these steps at any time during configuring.

Change the CLI prompt

Enter a 1- to 16-character string as the new prompt. For example, you could use the

prompt to indicate the controller’s name, such as “HSZ>.” Type the following command:

SET THIS_CONTROLLER PROMPT = “new prompt”

If you are configuring dual-redundant controllers, also change the CLI prompt on the other controller. Use the following command:

SET OTHER_CONTROLLER PROMPT = “new prompt”

See “SET controller” in Chapter 5, “CLI Commands.”

2–23

Set the maximum data-transfer rate

Use the following command:

SET THIS_CONTROLLER PORT_1_TRANSFER_RATE_REQUESTED = speed

SET THIS_CONTROLLER PORT_2_TRANSFER_RATE_REQUESTED = speed

If you are configuring dual-redundant controllers, also set the transfer rate for the other controller . Ho we ver , if you are running more t han one HSZ80 SCSI host port on the same bus, you must set their transfer rates to be identical. Use the following command:

SET OTHER CONTROLLER PORT_1_TRANSFER_RATE_REQUESTED=speed

SET OTHER CONTROLLER PORT_2_TRANSFER_RATE_REQUESTED=speed

See Chapter 5, “CLI Commands,” for more information about setting the data tran sfer rate.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

2–24 Configuring an HSZ80 Array Controller

UPS Support

NOTE: By default, the controller expects to use an external cache battery (ECB) as

backup power to the cache module. You can instead choose to use an uninterruptable power supply (UPS) to provide backup power in the event of a primary power failure.

Use the following command:

SET THIS_CONTROLLER CACHE_UPS

If you are configuring dual-redundant controllers, also indicate that the other

controller’s power is supported by a UPS. Use the following command:

SET OTHER_CONTROLLER CACHE_UPS

The other controller inherits the cache UPS setting for this controller. See “SET controller” in Chapter 5, “CLI Commands,” for details about set ting the

UPS. See T abl e 1–8 on page 1–23 and T ab le 1–9 on page 1–25 for information about cache

policies.

Setting the PVA Module ID Switch

The Power, Verification, and Addressing (PVA) module provides unique addresses to extended subsystems. Each BA370 rack-mountable enclosure in an extended subsystem must have its own PVA ID. Use PVA ID 0 for the enclosure that contains

the controllers. Use PVA IDs 2 and 3 for the additional enclosures. Figure 2–4 illustrates the PVA settings in an extended subsystem.

See the documentation that accompanied your enclosure for more details about the PVA and its settings.

2–25

First Expansion

Enclosure

SCSI Target ID = 11

SCSI Target ID = 10

SCSI Target ID = 9

SCSI Target ID = 8

EMU

NOTE: SCSI target IDs 4 and 5 are reserved. IDs 6 and 7 are used by the controllers.

PVA 2

Master

Enclosure

SCSI Target ID = 3

SCSI Target ID = 2

SCSI Target ID = 1

SCSI Target ID = 0

EMU

Controller A Controller B

PVA 0

Cache B Cache A

Second Expansion

SCSI Target ID = 15

SCSI Target ID = 14

SCSI Target ID = 13

SCSI Target ID = 12

Figure 2–4. SCSI Target ID Numbers on the Controller Device Bus and PVA Settings in an

Extended Subsystem

Enclosure

EMU

PVA 3

CXO5806B

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

2–26 Configuring an HSZ80 Array Controller

Establishing a Local Connection to the Controller

You can communicate with a controller locally or remotely. Use a local connection to configure the controller for the first time. Use a remote connection to your host system for all subsequent configuration tasks. See the Quick Setup Guide that came with your platform kit for details.

The maintenance port, as shown in Figure 2–5, provides a convenient way to connect a PC or terminal to the controller so that you can troubleshoot and configure it. This port accepts a standard RS-232 jack from any EIA-423 compatible terminal or a PC with a terminal-emulation program. The maintenance port supports serial communications with def a u lt values of 9600 baud using 8 data bits, 1 st op bi t , an d n o parity.

The maintenance port cable shown in Figure 2–5 has a 9-pin connector molded onto the end for a PC connection. If you need a terminal connection or a 25-pin connection, optional cabling is available and can be ordered. See Figure 1–5 on page 1–12 for an illustration.

2–27

1 2 3 4 5 6

Maintenance port

Maintenance port cable

CXO6484A

Figure 2–5. PC/Terminal to Maintenance Port Connection

CAUTION: The maintenance port described in this book generates, uses, and can radiate radio-frequency energy through cables that are connected to it. This energy may interfere with radio and television reception. Disconnect all maintenance port cables when you are not communicating with the controller.

Follow these steps to establish a local connection for setting the controller’s initial configuration:

1. Turn off the PC or terminal and connect it to the controller as shown in Figure 2–6.

a. Plug the maintenance port cable into the maintenance port for a PC

connection.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

2–28 Configuring an HSZ80 Array Controller

b. If you are using a terminal instead of a PC, you can order a cable from the

local field service office as shown in figure 1-5.

2. Turn on the PC or term inal.

3. Configure the P C or ter minal for 9600 baud, 8 data bits, 1 stop bit , and no parity . The default baud rate for the HSZ80 Array Controller is 9600, which makes communication between the two compatible.

4. Press the Enter or Return key. A copyright notice and the CLI prompt appear, indicating that you established a local connection with the controller.

5. Optional: Increase the data transfer rate to 19200 baud: a. Set the controller to 19200 baud with one of the following commands:

SET THIS_CONTROLLER TERMINAL sPEED=19200 SET OTHER_CONTROLLER TERMINAL sPEED=19200

b. Configure the PC or terminal for 19200 baud.

When you are entering CLI commands in a dual-redundant controller configuration,

remember that the controller to which you ’ re conn ected is this controller and the oth er controller is the “other controller” as shown in Figure 2–6.

Other controller

This controller

CXO5716A

Figure 2–6. “This Controller” and “Other Controller”

Selecting a Failover Mode

In selecting a failover mode, you have two choices: transparent failover or multiplebus failover. If you want the failover to occur without any intervention from the host, then transparent failover is best suited. The devices attached to the failed controller fail over to the surviving controller. With multiple-bus failover, the host intervenes during failover and sends commands to the companion controller.

Using Transparent Failover Mode

Transparent failover is a dual-redundant controller configuration in which two controllers are connected to the same host and device buses. Use this configuration if you want to use two controllers to service the entire group of storagesets, single-disk units, and other storage devices. Because both controllers service the same storage units, either controller can continue to service all of the unit s if its companion controller fails.

Distribute the I/O load between the two controllers in a transparent failover configuration using the following commands to specify which controller handles which targets and units:

2–29

n,n

)

SET THIS_CONTROLLER PORT_1_PREFERRED_ID = (

SET THIS_CONTROLLER PORT_2_PREFERRED_ID = (

Keep the following tips in mind if you configure controllers for transparent failover:

■ Set your controller s for tr ansparent fai lo v er before conf ig uring de v ices. By doin g

this, devices, storagesets, and units added to one controller’s configuration are automatically added to the other controller’s configuration.

■ If you decide to configure your devices before setting the controllers for

transparent failover, make sure you know which controller has the good configuration information before specifying SET FAILOVER COPY command. See Chapter 5 , “CLI Commands,” for details about setting the failover.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

2–30 Configuring an HSZ80 Array Controller

■ For better s ubsystem p erformance, balance y our assign ment of targ et ID numbers

across your dual-redundant pair of controlle rs. For example, if you are presenting four targets to the host, prefer two to one controller and two to the other controller.

■ Balance your assignment of devices. For example, in an 18-device subsystem,

place 3 devices on each of the 6 ports, rather than placing 6 devices on each of 3 ports.

■ The controller to which you copy configuration information restarts after you

enter the SET FAILOVER command.

Using Multiple-Bus Failover Mode

Multiple-bus (or host-assisted) failover is a dual-redundant controller configuration in which each controller has its own connection to the host. Thus, if one of the host connections to a controller fails, the host can cause units that became inaccessible to failover to the remaining viable connection. Because both controllers service the same storage units, either controller can continue to service all of the units if the other controller fails.

Keep the following points in mind when configuring controllers for multiple-bus failover:

■ The host distributes the I/O load between the controllers.

■ The host must have two SCSI adapters as well as operating-system software to

support the multiple-bus failover, dual-redundant controller configuration.

■ SCSI target ID number and LUN configurations on each controller must be

identical.

■ Mount both controllers in the same BA 37 0 rack -mou ntable enclo sure and follow

the steps in “Configuring an HSZ80 Array Controller,” page 2–3.

■ Partitioning is not supported.

Enabling Mirrored Write-Back Cache

Before configuring dual-redundant controllers and enabling mirroring, ensure the following condit ions are met:

■ Both controllers support the same size cache: 64 MB, 128 MB, 256 MB, or

512 MB.

■ Diagnostics indicates that both caches are good.

■ If you have not enabled the CACHE_UPS switch, then both caches have a battery

present. A battery does not have to be present for either cache if you enable the CACHE_UPS switch.

■ No unit errors are outstanding, for example, lost data or data that cannot be

written to devices.

■ Both controllers are started and configured in failover mode.

Selecting a Cache Mode

Before selecting a cache mode, you should understand the caching techniques supported by the cache module.

2–31

The cache module supports read, read-ahead, write-through, and write-back caching techniques that you can enable separately for each storage unit in a subsystem. For example, you can enable only read and write-through caching for some units while enabling only write-back caching for other units.

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2–32 Configuring an HSZ80 Array Controller

Fault-Tolerance

The cache module supports the following features to protect the availability of its unwritten (write-back) data:

■ Nonvolatile memory (required for write-back caching)

■ Dynamic caching techniques (automatic)

For details about these features, see “Fault-Tolerance for Write-Back Caching,” page 1–22.

Setting SCSI Target ID Numbers

In a subsystem, every SCSI device is assigned its own SCSI ID number. Setting an ID

number, though, really depends on which SCSI bus you are talking about—the host SCSI bus or the controller device bus, which are both shown in Figure 2–7.

2–33

Controller device bus

Figure 2–7. Host SCSI Bus and Controller Device Bus

Host SCSI Bus

Each BA370 rack-mountable enclosure in a configuration supports a range of SCSI target ID numbers. Each controller can access the target ID numbers that you specify with either of the following commands:

SET THIS_CONTROLLER PORT_1_ID = (

SET THIS_CONTROLLER PORT_2_ID = (

Host

Controller A

Host SCSI bus

n,n

)

n,n

)

Controller B

CXO6320A

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

2–34 Configuring an HSZ80 Array Controller

You can view IDs on this controller with the following command:

SHOW THIS_CONTROLLER FULL

You can view IDs on the other controller with the following command:

SHOW OTHER_CONTROLLER FULL

The valid target ID numbers are 0–15, with one ID reserved for each host controller on the host bus. When both ports are in use, the 16 target ID numbers are shared across ports. Once a target ID has been set on one port, that same target may not be used on the other port.

Using more than one target ID number allows the controller to present more units to the host. Enclose multiple ID numbers in parentheses and separate each by a comma:

(n1, n2, n3, . . .)

Device SCSI Bus

Device addressing allows the controller to identify the location of devices based on a port-target-LUN (PTL) number described in “Device PTL Addressing Convention within the Controller,” page 3–36.

Using Preferred ID Numbers

Use preferred SCSI target ID numbers to balance the I/O load of storage units among controllers and thereby improve the throughput for the dual-redundant pair of controllers.

You can specify a total of 15 SCSI target ID numbers across both host ports or you can specify 15 SCSI target ID numbers to either Port 1 or Port 2. Use the ID numbers you defined with the SET THIS_CONTROLLER PORT_1_ID (or PORT_2_ID) command.

Enclose multiple IDs in parentheses and sep a rate them by a comma. In a transparent failover configuration, the other controller automatically inherits the

newly defined ID numbers. During normal operation, each controller services only those storage units that are associated with its preferred ID numbers.

You can also use the PREFERRED_ID switch to effectively make the other controller a hot standby by declaring that it has no preferred SCSI target ID numbers. Use the following commands:

SET OTHER_CONTROLLER NOPORT_1_PREFERRED_ID = (

n,n

2–35

)

n,n

SET OTHER_CONTROLLER NOPORT_2_PREFERRED_ID = (

By declaring that it has no preferred IDs, this controller will not respond to any SCSI

target ID numbers on that port’s host SCSI bus. Instead, the other controller will process all I/O during norm al operation.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

)

Chapter 3 Creating Storagesets

This chapter provides information to help you create storagesets for your subsystem. The procedure in this chapter tak es you thro ugh th e planning steps and procedu res for creating storagesets.

3–1

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

3–2 Creating Storagesets

Introduction

Storagesets are implementations of RAID technology, also known as a Redundant Array of Independe nt Disks. Every storageset shares one important feature: each one

looks like a single storage unit to the host, regardless of the number of drives it uses. You can create storage units by combining disk drives into storagesets, such as

stripesets, RAIDsets, and mirrorsets, or by presenting them to the host as single-disk

units, as shown in Figure 3–1.

■ Stripesets (RAID 0) combine disk drives in serial to increase transfer or request

rates.

■ Mirrorsets (RAID 1) combine disk drives in parallel to provide a highly-reliable

storage unit.

■ RAIDsets (RAID 3/5) combine disk drives in serial—as do stripesets—but also

store parity data to ensure high reliability.

■ Striped mirrorsets (RAID 0+1) combine mirrorsets in serial and parallel to

provide the highest throughput and availability of any storage unit.

Controllers can support the number of RAIDsets as listed in Table 3–1. For a complete discussion of RAID, refer to The RAIDBOOK—A Source Book for

Disk Array Technology.

3–3

Unit

Stripeset

Mirrorset

RAIDset

Disk drives

Unit

Figure 3–1. Units Created from Storagesets, Partitions, and Drives

Partitioned disk drive

Unit

Partitioned storageset

Striped mirrorset

Unit

CXO5368B

Table 3–1 Controller Limitations for RAIDsets

Unit

RAIDset Type Limit Total number of RAID5 20 Total number of RAID5 + RAID1 30 Total number of RAID5 + RAID1 + RAID0 45

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3–4 Creating Storagesets

Planning and Configuring Storagesets

Use this procedure to plan and configure the storagesets for your subsystem. Use the references in each step to locate details about specific commands and concepts.

1. Create a storageset and device profile. See “Creating a Storageset and Device

Profile,” page 3–5 for suggestions about creating a profile.

2. Determine your storage r equirement s. Use the ques tions in “Determining S torage Requirements,” page 3–7 to help you.

3. Choose the type of s toragesets yo u need to u se in your s ubsystem. S ee “Choosin g a Storageset Type,” page 3–8 for a comparison and description of each type of storageset.

4. Select names for your storagesets and units. See “Creating a Storageset Map,” page 3–34 for details about selecting names.

5. Assign unit numbers to storagesets so the host can access the units. See “Node IDs,” page 3–30 for informat ion about how to assig n un it numbers to storagesets.

6. Create a storageset map to help you configure your subsystem. See “Creating a Storageset Map,” page 3–34 for suggestions about creating a storageset map.

7. If you are going to partition your storagesets, plan the partitions. See “Planning Partitions,” page 3–40 for information about p a rti tions and how to plan for them.

8. Choose the switches that you will want to set for your storagesets and devices. See“Choosing Switches for Storagesets and Devices,” page 3–42 for a description of the switches you can select for storagesets.

9. Configure the storagesets you have planned using one of these methods:

❏ Use StorageWorks Command Console (SWCC) to set up and manage RAID

storage subsystems. See the SWCC Getting Started Gui d e for d etails about using SWCC to configure your storagesets.

❏ Use CLI commands. This me thod al lo ws you fl ex ib ility in def in ing an d nam-

ing storagesets. See “Configuring Storagesets,” page 4–1 for information about configuring each type of storageset using CLI commands.

Creating a Storageset and Device Profile

Creating a profile for your storagesets and device s can help simplify the configuration process. This chapter helps you to choose the storagesets that best suit your n eeds and helps you to make informed decision s about the switches that you can enable for each storageset or storage device that you configure in your subsystem.

Familiarize yourself with the kinds of information contained in a storageset profile, as

shown in Figure 3–3. Appendix contains blank profiles that you can copy and use to record the details for

your storagesets. Use the information in this chapter to help you make decisions when creating storageset profiles.

3–5

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

3–6 Creating Storagesets

Type of Storageset

___ Mirrorset

Storageset Name.........

Disk Drives...................

Unit Number.................

✔ RAIDset ___ Stripeset ___ Striped Mirrorset

accept default values DISK10300, DISK20300, DISK30300

accept default

Partitions

Unit # Unit # Unit # Unit # Unit # Unit # Unit # Unit #

%%%%%%%%

RAIDset Switches

Reconstruction Policy Reduced Membership Replacement Policy

Normal (default)

✔

Fast

____

✔ No (default)

Yes, missing:

____

✔ Best performance

(default)

Best fit

____

None

____

Mirrorset Switches

Replacement Policy Copy Policy Read Source

___ Best performance (default)

Best fit

___

None

___

Normal (default)

___

Fast

___

Least busy (default) Round robin

___

Disk drive:

___

Initialize Switches

Chunk size Save Configuration Metadata

Automatic (default)

✔

64 blocks

____

128 blocks

____ ____

256 blocks Other:

____

____ No (default)

✔ Yes

✔ Destroy (default)

Retain

____

Unit Switches

Read Cache Read-Ahead Cache Maximum Cache Transfer Error Mode*

✔

____

Yes (default) No

✔ Yes (default)

____

✔ 32 blocks (default)

Other:

____

Write Cache Write Protection Availability

____ Yes (default)

✔ No

✔ No (default)

____

Yes

✔ Run (default)

____

NoRun

___

Normal Failsafe

___ *Valid only for

mirrorsets with DT support enabled

Figure 3–2. Storageset Profile

Determining Storage Requirements

Start the planning process by determining your storage requirements. Here are a few of the questions you should ask yourself:

■ What applications or user groups will access the subsystem? How much capacity

do they need?

■ What are the I/O requirements? If an application is data-transfer intensive, what

is the required transfer rate? If it is I/O-request intensive, what is the required response time? What is the read/write ratio for a typical request?

■ Are most I/O requests directed to a small percentage of the disk drives? Do you

want to keep it that way or balance the I/O load?

■ Do you store mission-critical data? Is availability the highest priority or would

standard backup procedures suffice?

Use your responses to these questions along with Table 3 –2 to determine the types of storagesets you should create to satisfy your organization’s requirements.

3–7

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

3–8 Creating Storagesets

Choosing a Storageset Type

Different applications may have different storage requirements, so you will probably want to configure more than one kind of storageset in your subsystem.

All of the storagesets described in this book implement RAID technology. Consequently, they all share one important feature: each storageset, whether it contains two disk drives or ten, looks like one large, virtual disk drive to the host.

Table 3–2 compares different kinds of storagesets to help you determine which ones satisfy your requirements.

Table 3–2 A Comparison of Different Kinds of Storagesets

Storageset Type Relative

Availability

Array of disk drives (JBOD) Stripeset (RAID 0)

Mirrorset (RAID1) RAIDset (RAID 3/5)

Striped Mirrorset (RAID 0+1)

Equivalent to a single disk drive Proportionate to number of disk drives; worse than single disk drive Excellent Good/Fair Good/Fair System drives; critical

Excellent Excellent/Fair Good/Poor High request rates,

Excellent Excellent if used

Request Rate

(Read/Write) I/O per

Identical to single disk drive Excellent if used with large chunk size

with large chunk size

second

Transfer Rate (Read/

Write) MB per

second Identical to single disk drive Excellent if used with small chunk size

Excellent if used with small chunk size

Applications

High performance for noncritical data

files

read-intensive, data lookup Any critical responsetime application

For a comprehensive discussion of RAID, refer to The RAIDBOOK—A Source Book for Disk Array Technology.

Using Stripesets to Increase I/O Performance

Stripesets enhance I/O performance by spreading the data across multiple disk dri ves.

Large I/O requests are broken into small segments called “chunks.” These chunks are then “striped” across the disk drives in the storageset, thereby allowing several disk drives to participate in one large I/O request or handle several I/O requests simultaneously.

For example, in a three-member stripeset that contains disk drives 10000, 20000, and 30000, the first chunk of an I/O request is written to 10000, the second to 20000, the third to 30000, the fourth to 10000, and so forth until all of the d a ta has been written to the drives.

3–9

Chunk 1

CXO5507A

Figure 3–3. Striping Lets Several Disk Drives Participate in Each I/O Request

The relationship between the chunk size and the average request size determines if striping maximizes the request rate or the data-transfer rate. You can set the chunk

size or let the controller set it automatically. See “Chunk Size,” page 3–51, for information about setting the chunk size.

Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide

3–10 Creating Storagesets

A major benefit of striping is that it balances the I/O load across all of the disk drives

in the storageset. This can increase the subsystem’s performance by eliminating the hot spots, or high localities of reference, that occur when frequently accessed data becomes concentrated on a single disk drive.

Considerations for Planning a Stripeset

Keep the following points in mind as you plan your stripesets:

■ A controller can support up to 45 storagesets, consisting of stripesets, mirrorsets

and RAIDsets (see Table 3–1).

■ Reporting methods and size li mitations prevent certain operating systems from

working with large stripesets. See the HSZ80 Array Controller ACS Version 8.3 Release Notes or the Quick Setup Guide that came with your software platform

kit for details about these restrictions .

■ A storageset should only contain disk drives of the same capacity. The controller

limits the capacity of each member to the capacity of the smallest member in the storageset when the storagest is initialized (the base member size). Thus, if you combine 9 GB disk driv es with 4 GB disk dri v es in the same storageset, the 4 GB disk drive will be the base member size and you will waste 5 GB of capacity on each 9 GB member.

If you need high performance and high availability, consider using a RAIDset, striped mirrorset, or a host-based shadow of a stripeset.

NOTE: A striped mirrorset cannot be created if the mirrorsets are enabled for DT_SUPPORT.

■ Striping does not protect against data loss. In fact, because the failure of one

member is equivalent to the failure of the entire stripeset, the likelihood of losing data is higher for a stripeset than for a single disk drive.

For example, if the mean time between failures (MTBF) for a single disk is one hour, then the MTBF for a stripeset that com pri ses N such disks is l/N hours. As another example, if a single disk’s MTBF is 150,000 hours (about 17 years), a stripeset comprising four of these disks wo uld only have an MTBF of slightly more than four years.

Compaq HSZ80 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

HSZ80 Array Controller ACS Version 8.3

About This Guide

Getting Help

Compaq Website

Te lephone Numbers

Precautions

Electrostatic Discharge Precautions

Component Precaution

VHDCI Cable Precautions

Maintenance Port Precautions

Conventions

Typographical Conventions

Special Notices

Required Tools

Related Publications

Revision History

Chapter 1

General Description

Typical Installation

Figure 1–1. Basic Building Block

Summary of HSZ80 Features

The HSZ80 Array Controller

Figure 1–2. Bridging the Gap Between the Host and Its Storage Subsystem

Figure 1–3. HSZ80 Array Controller

Table 1–3 HSZ80 Array Controller

Figure 1–4. Parts Used in Configuring the HSZ80 Array Controller

Figure 1–5. Optional Maintenance Port Cable for a Terminal Connection

Table 1–5 Parts of the Optional Maintenance Port Cable

Figure 1–6. Location of Controllers and Cache Modules

Operator Control Panel

Figure 1–7. HSZ80 Controller Operator Control Panel (OCP)

Maintenance Port

Utilities and Exercisers

Fault Management Utility

Virtual Terminal Display

Disk Inline Exerciser

Configuration Utility

HSUTIL

Code Load and Code Patch Utility

Clone Utility

Field Replacement Utility

Change Volume Serial Number Utility

Device Statistics Utility

Cache Module

Figure 1–8. Cache Module

Table 1–7 Location of Cache Module Parts

Caching Techniques

Read Caching

Read-Ahead Caching

Write-Through Caching

Write-Back Caching

Fault-Tolerance for Write-Back Caching

Nonvolatile Memory

Cache Policies Resulting from Cache Module Failures

External Cache Battery

Table 1–10 ECB Capacity Based on Memory Size

Figure 1–9. ECB for Dual-Redundant Controller Configurations

Table 1–11 Location of Parts

Charging Diagnostics

Battery Hysteresis

Chapter 2

Configuring an HSZ80 Array Controller

Introduction

Configuration Rules

Configuring an HSZ80 Array Controller

A Few Tips

Configuring a Single Controller

Figure 2–1. Cabling for a Single-Controller Configuration

Connecting a Single Controller to the Host

Configuring Dual-Redundant Controllers in Transparent Failover Mode

Figure 2–2. Cabling for a Dual-Redundant Controller Configuration in Transparent Failover

Connecting in Transparent Failover Mode to the Host

Configuring Dual-Redundant Controllers in Multiple-Bus Failover Mode

Figure 2–3. Cabling for a Dual-Redundant Controller Configuration in Multiple-Bus Failover

Connecting in Multiple-Bus Failover Mode to the Host

Optional Steps