hus vm block module hitachi thin image user guide v 73-03-3x

8/19/2019 Hus Vm Block Module Hitachi Thin Image User Guide v 73-03-3x

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Product Version

Contents

Getting Help

F AST F IND L INKS

Hitachi Unified Storage VM Block ModuleHitachi Thin Image User Guide

MK-92HM7010-05


2/164Hitachi Unified Storage VM Block Module Hitachi Thin Image User Guide

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© 2012-2014 Hitachi, Ltd. All rights reserved.

No part of this publication may be reproduced or transmitted in any form or by any means, electronic ormechanical, including photocopying and recording, or stored in a database or retrieval system for anypurpose without the express written permission of Hitachi, Ltd. (hereinafter referred to as "Hitachi") andHitachi Data Systems Corporation (hereinafter referred to as "Hitachi Data Systems").

Hitachi and Hitachi Data Systems reserve the right to make changes to this document at any time withoutnotice and assume no responsibility for its use. This document contains the most current information

available at the time of publication. When new and/or revised information becomes available, this entiredocument will be updated and distributed to all registered users.

Some of the features described in this document may not be currently available. Refer to the most recentproduct announcement or contact your local Hitachi Data Systems sales office for information about featureand product availability.

Notice: Hitachi Data Systems products and services can be ordered only under the terms and conditions ofthe applicable Hitachi Data Systems agreements. The use of Hitachi Data Systems products is governed bythe terms of your agreements with Hitachi Data Systems.

Hitachi is a registered trademark of Hitachi, Ltd. in the United States and other countries. Hitachi DataSystems is a registered trademark and service mark of Hitachi, Ltd. in the United States and other countries.

ShadowImage and TrueCopy are registered trademarks of Hitachi Data Systems.

AIX and IBM are registered trademarks or trademarks of International Business Machines Corporation.

Oracle and Java are registered trademarks of Oracle and/or its affiliates.

All other trademarks, service marks, and company names are properties of their respective owners.

Microsoft product screen shots reprinted with permission from Microsoft Corporation.


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Hitachi Unified Storage VM Block Module Hitachi Thin Image User Guide

Contents

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ixIntended audience. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xProduct version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xRelease notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x

Document revision level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xChanges in this revision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xReferenced documents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiDocument conventions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiConvention for storage capacity values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiiResources performing operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xiii

Accessing product documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xiiiGetting help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xiiiComments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xiii

1 Overview of Thin Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1Thin Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2Components of Thin Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

Components of volumes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4Consistency and snapshot groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4Thin Image overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4Dynamic Provisioning overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4The Command Control Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

How Thin Image works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5Thin Image Pools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

Virtual volumes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

Releasing V-VOL definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6Thin Image pairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6Storing snapshot data for a group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7Snapshot data storage methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9Differences in methods to storing snapshots depending on volumes . . . . . 1-10Restoring Thin Image pairs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10Deleting snapshot data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11



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Deleting Thin Image pairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11HTI pair status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12Copy threshold option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13Interoperability with other software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14

Data Retention Utility. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15 Volume Migration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17ShadowImage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17

TrueCopy and Universal Replicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-19Dynamic Provisioning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-21Resource Partition Manager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-22

Software application acronyms and abbreviations . . . . . . . . . . . . . . . . . . . . . 1-22

2 Planning and design requirements . . . . . . . . . . . . . . . . . . . . . . . . 2-1System requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Requirements for Thin Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2Installing Thin Image. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2Uninstalling Thin Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Requirements for licensed capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2Shared memory requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

Volume requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3Consistency group requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6Snapshot group requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7

Requirements for Thin Image operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7Calculating the number of virtual volumes that the storage system can

create . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7Calculating the number of Thin Image pairs that you can create . . . . . . . . 2-7

Calculating the number of Thin Image pairs based on pair tables. . . . . . 2-8Calculating the number of Thin Image pairs based on the snapshot

estimated manageable capacity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8Calculating the number of Thin Image pairs workflow . . . . . . . . . . . . . . . . 2-8Calculating the number of cache management devices . . . . . . . . . . . . . . . 2-9

The number of cache management devices required for Thin Imagepair operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9

Effects on I/O performance of the storage system . . . . . . . . . . . . . . . . . . 2-9Notes on assigning the pool capacity. . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9

Estimating the capacity of snapshot data to be copied to the pool . . . . 2-10Using external volumes as pool-VOLs . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10

3 Performing configuration operations. . . . . . . . . . . . . . . . . . . . . . . 3-1Configuration workflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2Creating pools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2Creating V-VOLs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

Changing the V-VOL settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7Removing V-VOLs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

Setting up command devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7


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4 Pair operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1Creating HTI pairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Using Storage Navigator to create HTI pairs workflow . . . . . . . . . . . . . . . . 4-3 Acquiring snapshot data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5

Acquiring snapshot data using the At-Time Snapshot function . . . . . . . . . . 4-6 At-Time Snapshot when Thin Image volume shared with UR and TC. . . . . . 4-6

Notes on using Thin Image primary volumes as TrueCopy or UniversalReplicator pair volumes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9

Notes on acquiring snapshot data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9Restoring pairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10Deleting snapshot data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10Deleting pairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11

5 Monitoring and maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1Monitoring pair information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2

Viewing the number of pairs and a list of pairs . . . . . . . . . . . . . . . . . . . . . 5-2Checking pair status. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2

Monitoring pair properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2Monitoring synchronous rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

Monitoring consistency groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4 Viewing the number of consistency groups. . . . . . . . . . . . . . . . . . . . . . . . 5-4 Viewing a list of consistency groups. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4 Viewing properties of a consistency group . . . . . . . . . . . . . . . . . . . . . . . . 5-4

Monitoring pair operation history. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4 Viewing the operation run history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5Monitoring pair operation history using the secondary window. . . . . . . . . . 5-5

Monitoring licensed capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8Monitoring the number of cache management devices . . . . . . . . . . . . . . . . . . 5-8Managing pools and V-VOLs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8

Monitoring pool information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8 Viewing used pool capacity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9

Viewing used capacity by pool. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9 Viewing used pool capacity by HTI P-VOL . . . . . . . . . . . . . . . . . . . . . . 5-9

Pool capacity and formatting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9 Viewing formatted pool capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10Increasing pool capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10Changing the pool threshold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11Changing the pool name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11Recovering pools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12Deleting pools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13Changing V-VOL names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13Deleting V-VOLs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14

Viewing snapshot data capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14Maintenance requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15

Replacing the microcode offline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15



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Switching off the power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15

6 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1General troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2

Blocked pool recovery workflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5Processing pool-related SIMs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5Completing warning SIMs before depletion of cache management devices . 6-6

Contacting the Hitachi Data Systems Support Center . . . . . . . . . . . . . . . . . . . 6-7

A Command Control Interface command reference. . . . . . . . . . . . . . A-1Statuses required for CCI operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2

Pair status names in the CCI. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2Troubleshooting with the Command Control Interface. . . . . . . . . . . . . . . . . . . A-3

Identifying errors using the log on the CCI window. . . . . . . . . . . . . . . . . A-10Identifying errors using the CCI operation log file . . . . . . . . . . . . . . . . . . A-10

B Thin Image GUI reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1Replications window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2Local Replications window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3

View Pair Properties window. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-10 View Pair Synchronous Rate window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-12 View Histories window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-13Consistency Group Properties window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-15Create Pairs wizard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-16

Select Pair Configuration window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-17Select Primary Volumes window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-18Select Pool window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-21Select Secondary Volumes window . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-22Confirm window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-26

Split Pairs wizard. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-28Split Pairs window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-28Confirm window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-30

Resync Pairs wizard. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-32Resync Pairs window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-32Confirm window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-34

Delete Pairs window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-36Edit Local Replica Options wizard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-38

Edit Local Replica Options window . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-38Confirm window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-39

SI/TI System Options table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-40

Glossary


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Index



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Preface ix


Preface

This document describes and provides instructions for using Hitachi ThinImage (HTI) to plan, configure, and perform pair operations on the HitachiUnified Storage VM (HUS VM) storage system.

Please read this document carefully to understand how to use this product,and maintain a copy for reference purposes.

This preface includes the following information:

□ Intended audience

□ Product version

□ Release notes

□ Document revision level

□ Changes in this revision

□ Referenced documents

□ Document conventions

□ Convention for storage capacity values

□ Resources performing operations

□ Accessing product documentation

□ Getting help

□ Comments



x Preface

Intended audienceThis document is intended for system administrators, Hitachi Data Systemsrepresentatives, and authorized service providers who are involved ininstalling, configuring, and operating the Hitachi Virtual Storage Platformstorage system.

This document is for users who are familiar with the following:

• Data processing and RAID storage systems and their basic functions.• The Hitachi Virtual Storage Platform storage system, and have read the

Hitachi Virtual Storage Platform User and Reference Guide .

• The Storage Navigator (SN) software for the HUS VM and have read theHitachi Storage Navigator User Guide .

• Hitachi Dynamic Provisioning, Hitachi Dynamic Tiering software, HitachiLUN Manager, Hitachi LUN Expansion, Virtual LUN, and the Hitachi DataRetention Utility.

Product version

This document revision applies to HUS VM microcode 73-03-3 x or later.

Release notesThe Hitachi Unified Storage VM Release Notes provide information about theHUS VM microcode (DKCMAIN and SVP), including new features andfunctions and changes. The release notes are available on the Hitachi DataSystems Portal: https://portal.hds.com

Document revision level

Changes in this revision• Updates regarding pair operations during zero-page reclamation.

• Updates regarding pair operation rejection when system option mode905 is ON.

Revision Date Description

MK-92HM7010-00 December 2012 Initial release.

MK-92HM7010-01 January 2013 Supersedes and replaces MK-92HM7010-00.

MK-92HM7010-02 March 2013 Supersedes and replaces MK-92HM7010-01.

MK-92HM7010-03 May 2013 Supersedes and replaces MK-92HM7010-02.

MK-92HM7010-04 October 2013 Supersedes and replaces MK-92HM7010-03.

MK-92HM7010-05 September 2014 Supersedes and replaces MK-92HM7010-04.

https://portal.hds.com/https://portal.hds.com/


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• Updates to ShadowImage on page 1-17 and Creating HTI pairs on page4-2 regarding MU numbering.

• Update to Switching off the power supply on page 5-15 regarding sharedmemory.

• Added section Viewing used pool capacity on page 5-9 .

• Added section Viewing snapshot data capacity on page 5-14 .

Referenced documentsHitachi Unified Storage VM documentation:

• Hitachi Storage Navigator User Guide , MK-92HM7016

• Hitachi Universal Volume Manager User Guide , MK-92HM7020

• Hitachi Volume Shredder User Guide , MK-92HM7021

• Hitachi Unified Storage VM Block Module Provisioning Guide , MK-92HM7012

• Hitachi TrueCopy® User Guide , MK-92HM7018

• Hitachi Universal Replicator User Guide , MK-92HM7019

• Command Control Interface User and Reference Guide , MK-90RD7010

• Hitachi Command Control Interface Command Reference , MK-90RD7009

Document conventionsThe following table lists the typographical conventions used in thisdocument.

Convention Description

Bold Indicates text on a window, other than the window title,including menus, menu options, buttons, fields, and labels.Example: Click OK .

Italic Indicates a variable, which is a placeholder for actual textprovided by the user or system. Example: copy source-file target-file

Monospace Indicates text that is shown on screen or the user types.Example: # pairdisplay -g oradb

< > angled brackets Indicates a variable, which is a placeholder for actual textprovided by the user or system. Example: # pairdisplay -g

Note: Italic font is also used to indicate variables.

[ ] square brackets Indicates optional values. Example: [ a | b ] indicates that youcan choose a, b, or nothing.

{ } braces Indicates required or expected values. Example: { a | b }indicates that you must choose either a or b.



xii Preface

This document uses the following icons to draw attention to information.

Convention for storage capacity valuesPhysical storage capacity values (for example, disk drive capacity) arecalculated based on the following values.

Logical storage capacity values (for example, logical device capacity) arecalculated based on the following values.

| vertical bar Indicates that you have a choice between two or more optionsor arguments. Examples:

[ a | b ] indicates that you can choose a, b, or nothing.

{ a | b } indicates that you must choose either a or b.

Convention Description

Icon Meaning Description

Tip Provides helpful information, guidelines, or suggestions forperforming tasks more effectively.

Note Calls attention to important and/or additional information.

Caution Warns the user of adverse conditions and/or consequences(for example, disruptive operations).

WARNING Warns the user of severe conditions and/or consequences (forexample, destructive operations).

Physical capacity unit Value

1 KB 1,000 bytes

1 MB 1,000 2 bytes

1 GB 1,000 3 bytes

1 TB 1,000 4 bytes

1 PB 1,000 5 bytes

1 EB 1,000 6 bytes

Logical capacity unit Value

1 KB 1,024 bytes

1 MB 1,024 KB or 1,024 2 bytes

1 GB 1,024 MB or 1,024 3 bytes

1 TB 1,024 GB or 1,024 4 bytes

1 PB 1,024 TB or 1,024 5 bytes

1 EB 1,024 PB or 1,024 6 bytes


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Preface xiii


Resources performing operationsThe resources for each operation must satisfy the specific conditions to usethe functions described in this document.

The SN main window shows only the resources that are assigned to a userwho logs into the SN. The window may also show the related resources thatare required to manage the assigned resources.

The SN secondary window shows all of the resources in the storage system.To perform an operation in the SN secondary window, verify the resourcegroup ID in the Basic Information Display dialog boxes and then perform theoperations for the resources assigned to the user account.

For more information about user accounts, see the Hitachi StorageNavigator User Guide .

Accessing product documentationThe HUS VM user documentation is available on the Hitachi Data SystemsPortal: https://portal.hds.com . Check this site for the most currentdocumentation, including important updates that may have been madeafter the release of the product.

Getting helpThe Hitachi Data Systems Support Center staff is available 24 hours a day,seven days a week. If you need technical support, log on to the Hitachi DataSystems Portal for contact information: https://portal.hds.com

CommentsPlease send us your comments on this document:[email protected] . Include the document title and number, includingthe revision level (for example, -03), and refer to specific sections andparagraphs whenever possible. All comments become the property ofHitachi Data Systems.

Thank you!

1 block 512 bytes

Logical capacity unit Value

https://hdssupport.hds.com/https://hdssupport.hds.com/https://hdssupport.hds.com/https://hdssupport.hds.com/



xiv Preface


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1

Overview of Thin Image 1–1


Overview of Thin Image

This document provides an overview of Thin Image (HTI). Use HTI toperform cost-effective duplication by storing differential data betweenprimary volumes (P-VOLs) and secondary volumes (S-VOLs) of virtualvolumes (V-VOLs).

This chapter includes the following information:

□ Thin Image

□ Components of Thin Image

□ How Thin Image works

□ HTI pair status

□ Copy threshold option

□ Interoperability with other software

□ Software application acronyms and abbreviations



1–2 Overview of Thin Image

Thin ImageUse HTI to create duplicated data in your storage system for data in open-system volumes. Splitting HTI pairs stores snapshot data. HTI storessnapshots of data in your storage system. You can store a maximum of1,024 snapshots. If a data failure occurs in your storage system, use thesnapshot data to restore the data.

The following figure shows an overview of HTI.

Snapshot data is a copy of updated data in HTI P-VOL. Before the P-VOL isupdated, only the updated data is copied as snapshot data in pool volumes(pool-VOLs). This processing is referred to as the storing of snapshot data.

Create HTI pairs to store snapshot data. The P-VOL of an HTI pair is a logicalvolume. The S-VOL of an HTI pair is a V-VOL.

Use the following process to store snapshot data:

1. Create an HTI pair.

2. The host updates the P-VOL.

3. You split the HTI pair.

The P-VOL snapshot data is stored (Snapshot A in the following figure).

4. The host updates the P-VOL again.

5. You split the HTI pair.

The updated data in the P-VOL is stored as snapshot data (Snapshot Bin the following figure).

The following image shows the workflow to store snapshot data.


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In the figure above, the host can reference the P-VOL, snapshot data A, andSnapshot data B. Snapshots A and B are handled as HTI S-VOLs.

Required software applications

Dynamic Provisioning (DP) is required to use HTI. DP accesses data in pool-VOLs by way of V-VOLs, and can handle data in open-system servers suchas UNIX and PC servers.

Components of Thin ImageAn HTI system typically consists of the following components:

• HTI pairs:

Components of P-VOL, S-VOL, and pool-VOLs

• Groups:

A consistency group

A snapshot group

• Software applications:

HTI

DPCommand Control Interface (CCI)




Components of volumesHTI manages logical volumes of P-VOLs and V-VOLs of S-VOLs as HTI pairs.Logical volumes of P-VOLs include V-VOLs whose provisioning type is DP.You can only use the V-VOL used by an HTI pair as an S-VOL. Thedifferential data of P-VOLs are stored as snapshot data in pool-VOLs.

The following volumes are required for using HTI:

• At least one P-VOL

• At least one S-VOL (V-VOL)

• At least one HTI pool-VOL, as a container for snapshot data

Consistency and snapshot groupsTo use HTI to create new pairs and perform HTI pair operations per group,add pairs to a consistency group or a snapshot group.

Using the CCI, you can create multiple HTI pairs as a consistency group. Tostore snapshot data per consistency group, first define the consistencygroup. Use consistency groups to assure the data from the time when HUS

VM receives the request of storing data.The following table lists the differences between consistency groups andsnapshot groups.

For more information about storing snapshot data for a group, see Storingsnapshot data for a group on page 1-7 .

For more information about consistency group requirements, seeConsistency group requirements on page 2-6 .

Thin Image overviewYou use the HTI on your SN computer.

The use of HTI, DP, and all other VSP products requires license agreementswith Hitachi.

Dynamic Provisioning overviewInstall DP on the SN computer to perform HTI pair operations. DP license isrequired. You must reserve license capacity enough to accommodate pairsor pools that should be created.

Item Consistency group Snapshot group

Maximum number of pairs in a group 8,192 8,192

Maximum number of groups you cancreate

256* 512

Data consistency Guaranteed Not guaranteed

* You can create up to 256 consistency groups in a storage system, with ShadowImage(SI) and HTI consistency groups combined.


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The licensed capacity for DP is calculated based on the capacity of pool-VOLs for HTI and DP. These volumes are referred to as used volumes. Makesure that the licensed capacity exceeds the total capacity of used volumes.

The Command Control InterfaceYou use the CCI from a host and run commands to perform HTI pairoperations.

For more information about the commands you can run to perform HTI pairoperations, see Command Control Interface command reference on page A-1 and the Hitachi Command Control Interface Command Reference .

How Thin Image worksThis topic explains how HTI works and includes the following:

• Thin Image Pools on page 1-5

• Virtual volumes on page 1-6

• Thin Image pairs on page 1-6

• Storing snapshot data for a group on page 1-7• Snapshot data storage methods on page 1-9

• Differences in methods to storing snapshots depending on volumes onpage 1-10

• Restoring Thin Image pairs on page 1-10

• Deleting snapshot data on page 1-11

• Deleting Thin Image pairs on page 1-11

Thin Image Pools

HTI stores snapshot data in pools. A pool consists of multiple pool-VOLs,which contain snapshot data. A pool can contain up to 1,024 pool-VOLs. Youcan create up to 128 pools in a storage system including DP, DynamicTiering (HDT), and HTI pools.

The following figure illustrates the relationship between an HTI pair and apool.




You must create pools to use HTI. If you are using HTI to perform a pairoperation, you can add pool-VOLs but you cannot delete pool-VOLs. Todelete a pool, delete all HTI pairs.

Virtual volumesV-VOLs do not have any physical storage space. You must create the V-VOLsbefore you create HTI pairs because HTI uses V-VOLs as S-VOLs.

Releasing V-VOL definitions

Release V-VOL definitions only if the V-VOL is not being used as an HTI S-VOL. To release definitions of V-VOLs, release the HTI pairs that are usingthe V-VOLs.

Thin Image pairsUse the following process to create HTI pairs:

1. Create the V-VOLs. You can specify up to 1,024 S-VOLs for a single P-VOL.

You cannot use volumes that have recently changed to “SMPL” status tocreate HTI pairs. Releasing an HTI pair changes the volume status to

“SMPL”.

Caution: The pool capacity is the total capacity of pool-VOLs in the pool.If data is written to HTI pair volumes and therefore the amount of poolusage exceeds the pool capacity, the status of the HTI pair changes to

“PSUE”, which means that a failure occurs, and then you cannot storesnapshot data. Also, you cannot create new HTI pairs. You must reserve asufficient amount of pool capacity for the pools you plan to create.


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For more information about releasing HTI pairs, see Deleting pairs onpage 4-11 .

To create HTI pairs using volumes that are in “SMPL” status, wait tocreate the pairs.

2. Create the HTI pairs. Specify the pool to be used for the HTI pair.

If multiple HTI pairs share the same P-VOL, the pairs must also sharethe same pool. For example, if you specify three S-VOLs for one P-VOL,

you must specify the same pool for the three HTI pairs.For more information about creating HTI pairs, see Creating HTI pairs onpage 4-2 .

Storing snapshot data for a groupUse the CCI to define a consistency group or a snapshot group and storesnapshot data for the group. The following figure illustrates how snapshotdata for a group is stored.

For more information about the differences between snapshot groups andconsistency groups, see Consistency and snapshot groups on page 1-4 .

The following figure shows how snapshot data is stored for a group.




Snapshot data is stored in the following steps:

1. Request to store snapshot data for a group. To do this, run the followingCCI command:

raidcom modify snapshot -snapshot_data create

Note: Use the CCI to store snapshot data for consistency groups orsnapshot groups. Use the SN to reference consistency groups andsnapshot groups.


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2. The host issues a write request to each P-VOL in the group.

3. Snapshot data for the volumes are stored.

Snapshot data storage methodsUse the Copy-On-Write (COW) method or the Copy-After-Write (CAW)method to store snapshot data. In the COW method, after the P-VOLsnapshot data is acquired, the status changes to the write completion

status. In the CAW method, after writing data to the P-VOL the statuschanges to the write completion status. Therefore, the CAW method’swaiting time is shorter than that of the COW method.

The following image shows the CAW method.

In the CAW method, store snapshot data in the following steps:

1. The host writes data to a P-VOL.2. The write completion status is returned to the host before the snapshot

data is stored.

3. Snapshot data for the P-VOL is stored in the background.

The following image shows the COW method.




In the COW method, store snapshot data in the following steps:

1. The host writes data to a P-VOL.

2. Snapshot data for the P-VOL is stored.3. The write completion status is returned to the host after the snapshot

data is stored.

Differences in methods to storing snapshots depending onvolumes

If the write pending rate is less than 60% in the cache memory, use theCAW method to store the snapshot data. Otherwise, use the COW methodto store the snapshot data.

For more information about the write pending rate, see the Hitachi Unified

Storage VM Block Module Performance Guide .

If a P-VOL is an external volume

Use the COW method to store snapshot data.

Restoring Thin Image pairsYou can use HTI to overwrite snapshot data in pools to P-VOLs. Overwritingsnapshot data returns the P-VOL content to the condition it was when youstored the snapshot data. Overwriting snapshot data to P-VOLs is referredto as restoring HTI pairs.

If you write data to an S-VOL, this particular data (not the snapshot data)is overwritten to the P-VOL when you restore the HTI pair.

If a problem occurs with a P-VOL due to a failure, restore the pair so thatdata in the P-VOL is returned to the condition it was when you stored thesnapshot data.


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For more information about restoring pairs, see Restoring pairs on page 4-10 .

Deleting snapshot dataIf the capacity of snapshot data exceeds the pool capacity because of databeing written to HTI pair volumes, the pair changes to “PSUE”. An HTI pairin “PSUE” status shows that a failure has occurred. You cannot create new

HTI pairs in “PSUE” status. You must delete unneeded snapshot data.Use one of the following methods to delete snapshot data:

• Delete the HTI pairs.

Deleting an HTI pair deletes the snapshot data from the pool and unpairsthe P-VOL and S-VOLs.

• Delete only the snapshot data.

To delete snapshot data, use the Resync pairs window. If you onlydelete the snapshot data, the relationship between the P-VOL and S-VOLs is maintained. If you only delete the snapshot data, assign the MUnumber of the deleted snapshot data when snapshot data for the HTI

pair is stored.For more information about deleting snapshot data, see Deleting snapshotdata on page 4-10 .

After you delete snapshot data, the pair status changes to “PAIR” and youcannot store a snapshot even when the hosts update P-VOLs. To resumestoring snapshot data, split the pair again.

Deleting snapshot data or HTI pair takes time. The more pool capacity thepair uses, the longer it takes to split the pair. The more pairs are operatedconcurrently, the longer it takes to split the pair.

Deleting Thin Image pairsTo delete HTI pairs, use the Delete Pairs window. Delete a pair when youno longer need it or you want to delete snapshot data. Deleting a pairchanges the P-VOL and S-VOLs status to “SMPL(PD)” and then to “SMPL”.When the pair status changes to “SMPL”, the HTI pair is removed from SN.After you have deleted the HTI pairs, you can use the volumes in anotherpair.

You cannot create pairs when the status is “SMPL (PD)”. To shorten the timewhen the pair status is “SMPL (PD)”, complete the following:

1. Delete the snapshot data.

The pair status changes to “PAIR”.

2. Delete the pair.

If you have defined a snapshot group, when all of the pairs in the snapshotgroup change to “SMPL” status, the snapshot group is deleted. Make surethat the snapshot group is deleted, and then perform the next pairoperation.

For more information about deleting pairs, see Deleting pairs on page 4-11




HTI pair statusThe status of an HTI pair changes as you create, split, or perform other pairoperations on the pair, as illustrated in the following figure.

1. The volumes are not paired. The volumes are in “SMPL” status.

2. You create a pair. The initial copy is in progress. The pair status changesto “COPY”.

The pair is created. The pair status changes to “PAIR”.

3. Split the pair in “PAIR” status. The snapshot data is stored. The pairstatus changes to “PSUS”.

Note: Creating HTI pairs can take more time than usual if you createa pair immediately after deleting the last snapshot data for the P-VOL.

If you exceed the pool threshold while the HTI pair is in “PAIR” status,the pair status changes to “PFUL”. You cannot create additional HTI pairswhen you have exceeded the pool threshold.

Note: If you exceed the pool threshold while the HTI pair is in “PSUS”status, the pair status changes to “PFUS”.


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4. If you only want to delete snapshot data but you do not want to releasethe HTI pair, delete the snapshot data for the pair in “PFUS” status. Ifyou want to release the HTI pair, delete the pairs.

For more information about deleting pairs, see Deleting Thin Image pairson page 1-11 .

5. Restore the HTI pair in “PSUS” status. The snapshot data is overwrittento the P-VOL. While the pair is being restored, the pair status is “RCPY”.

The restore process finishes. The pair status changes to “PAIR”.The pool can only contain data of predetermined capacity. If the totalcapacity of snapshot data in the pool exceeds the pool capacity, a failureoccurs during the restore process, or if the pool usage rate reaches100%, the status of the HTI pair changes to “PSUE”. Even if the restoreprocess is not in progress, the pair status may change to “PSUE” if afailure occurs.

Hosts can read from or write to the HTI pair’s P-VOL or S-VOLs dependingon the status of HTI pairs. The following table explains the details.

Copy threshold optionI/O performance of the host server might be lowered as the workload on thestorage system increases. If you perform HTI restore operations when theworkload on the storage system is high, I/O performance of the host serveris more likely to be lowered because replication processes for the P-VOLsare triggered.

HTI pair status

P-VOL S-VOL

Read Write Read Write

SMPL Yes Yes No No

SMPL(PD) Yes Yes No No

COPY Yes Yes No No

PAIR/PFUL Yes Yes No No

PSUS/PFUS Yes Yes Yes Yes

RCPY Yes Yes No No

PSUE Yes Yes No No

Legend

Yes: Hosts can access the volumeNo: Hosts cannot access the volume

Caution: If a host uses an application to monitor HTI pair volumes,abnormal termination may occur depending on the status of an S-VOL. Forexample, a monitoring application may terminate abnormally if access fromthe application is rejected, because S-VOLs in a status other than “PSUS”and “PFUS” reject access from hosts. If a host connects to two or moreports, an abnormality may occur with ports that are not connected to S-VOLs rejecting access from hosts. To resolve these issues, you mustterminate the application that monitors volumes.




Use the copy threshold option to temporarily stop the replication processestriggered by the restore operations when the workload on the storagesystem is high. The copy threshold option can contribute to minimizing thedecline in I/O performance of the host server.

The copy threshold option is applicable only when the workload on thestorage system is excessively heavy. If you apply the copy threshold option,all of the replication processes triggered by restore operations are stopped.

Replication processes stopped by the copy threshold option are restarted asthe workload on the storage system is lowered. Enabling the copy thresholdoption stops replication processes for HTI and the following softwareapplications when the storage system is overloaded:

• SI

• Volume Migration

For more information about the copy threshold option, call the SupportCenter.

Interoperability with other softwareCreate HTI pairs using pair volumes for replication software applicationssuch as SI and TrueCopy (TC), or using volumes to which attributes aredefined by Data Retention Utility or Command Control Interface.

The following table explains whether you can share pair volumes by HTI andother software applications.

Software application volume types Used as HTI P-VOL Used as HTI S-VOL

SI P-VOL Yes 3 No

SI S-VOL Yes No

SI reserve volume No No

TC P-VOL Yes No

TC S-VOL Yes No

Universal Replicator (UR) P-VOL Yes No

UR S-VOL Yes No

UR journal volume No No

Volume Migration source volume No No

Volume Migration target volume No No

Volume Migration reserve volume No No

High Availability Manager (HAM) P-VOL No No

HAM S-VOL No NoHAM quorum disk No No

Nondisruptive Migration No No

Read Only volume 1, 4, 6 Yes Yes

Protect volume 1, 4, 6 Yes Yes

"S-VOL Disable" volume 4, 6 Yes No


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Data Retention UtilityCreate HTI pairs using volumes that have access attributes assigned byData Retention Utility. The access attributes determines the pair operationsand pool operations that you can perform using HTI.

The following tables explain whether you can perform HTI pair operationsand pool operations on volumes that have access attributes assigned byData Retention Utility.

Also, you can assign access attributes to HTI P-VOL and S-VOLs. The tablesbelow also explain HTI pair operations and pool operations after accessattributes are assigned.

Zero Read Capacity volume 2, 5 Yes Yes

Invisible volume 2, 5 Yes Yes

Reserve volume Yes Yes

DP-VOL Yes No

1. (If you use SN to share the volume with other software applications) The pair status

determines whether you can share the volume.2. Use the CCI to share the volume with other software applications.

Note: You cannot use the SN to do share volumes.

3. You cannot Quick Restore.

4. The Data Retention Utility is required to set Read Only, Protect, and S-VOL Disableattributes.

5. The CCI is required to set the Zero Read Capacity and Invisible attributes.

6. Use Data Retention Utility to confirm whether Read Only, Protect, S-VOL Disable,Zero Read Capacity and Invisible attributes are set to volumes.

Yes: You can share the volume

No: You cannot share the volume

Software application volume types Used as HTI P-VOL Used as HTI S-VOL

P-VOLaccess

attribute

S-VOLaccess

attribute

HTI pair operation

Createpair Split pair

Suspendpair

Resyncpair

(NormalCopy)

Resyncpair

(ReverseCopy)

Delete pair

Read/Write

Read/Write

Yes Yes Yes Yes Yes Yes

ReadOnly

No No No No No No

Protect No No No No No No

S-VOLDisable

No No No No No No




The following table show when Data Retention Utility can assign accessattributes to HTI P-VOL and S-VOLs based on the HTI pair status.

ReadOnly,

Protect,S-VOLDisable

Read/Write

Yes Yes Yes Yes No Yes

ReadOnly

No No No No No No

Protect No No No No No No

S-VOLDisable

No No No No No No

Legend

Yes: You can perform the pair operation

No: You cannot perform the pair operation

Access attribute of volume specified byHTI

HTI pool operation

Pool-VOL setting

Read/Write Yes

Read Only No

Protect No

S-VOL Disable No

Legend


No: You cannot perform the pair operation

Note: HTI pair operations do not change volume access attributes.Performing a reverse resynchronization does not copy S-VOLs to P-VOLsaccess attributes when writing snapshot data to P-VOLs.

P-VOLaccess

attribute

S-VOLaccess

attribute

HTI pair operation

Createpair Split pair

Suspendpair

Resyncpair

(NormalCopy)

Resyncpair

(ReverseCopy)

Delete pair

HTI volume Access attribute to be assigned

Pair status Volume Read/WriteRead Only

ProtectS-VOL Disable

COPY P-VOL Yes YesS-VOL Yes No

PAIR, PFUL P-VOL Yes Yes

S-VOL Yes Yes

PSUS, PFUS P-VOL Yes Yes

S-VOL Yes Yes


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Volume MigrationYou cannot perform HTI pair operations on volumes in migration plans,

regardless of the status of the migration plans. Also, you cannot use HTIpair volumes or pool-VOLs for Volume Migration migration plans.

ShadowImageYou can share HTI P-VOLs with SI P-VOL and S-VOLs. The following tableslist the relationship between pair operations and status.

The following table shows the HTI pair operations that you can performbased on the SI pair status.

The following table shows the HTI pair operations that you can performbased on the SI pair status.

SMPL(PD) P-VOL Yes Yes

S-VOL Yes No

RCPY P-VOL Yes NoS-VOL Yes No

PSUE P-VOL Yes Yes

S-VOL Yes No

Legend

Yes: You can perform the setting

No: You cannot perform the setting

HTI volume Access attribute to be assigned

Pair status Volume Read/WriteRead Only

ProtectS-VOL Disable

HTI pairoperation

SI pair status

COPY(PD)/

COPY

PAIR

COPY(SP)/

COPY

PSUS(SP)/

PSUS

PSUS

COPY(R S)/

COPY

COPY(RS-R)/RCPY

PSUE

Create pair Yes Yes Yes Yes Yes Yes No Yes

StoreSnapshotdata

Yes Yes Yes Yes Yes Yes No Yes

Restore pair No No No No Yes No No Yes

DeleteSnapshotdata

Yes Yes Yes Yes Yes Yes Yes Yes

Release pair Yes Yes Yes Yes Yes Yes Yes YesLegend


No: You cannot perform the pair operation (the command is rejected)




The following table shows the SI pair operations that you can perform basedon the HTI pair status.

HTI pairoperation

SI pair status

COPY(PD)/

COPY

PAIR

COPY(SP)/COPY

PSUS(SP)/

PSUS

PSUS

COPY(R S)/

COPY

COPY(RS-R)/

RCPY

PSUE

Create pair No No No No Yes No No No

Store Snapshot

data

N/A No No No Yes No No No

Store Snapshotdata for aconsistencygroup

N/A No No No Yes* No No No

Restore pair N/A No No No Yes No No No

DeleteSnapshot data

N/A Yes Yes Yes Yes Yes Yes Yes

Release pair N/A Yes Yes Yes Yes Yes Yes Yes

* The status of the SI pair must be “PSUS” during the period between when HTI startsto store snapshot data for a consistency group and when the status of all pairs in theconsistency group changes to “PSUS”. If the SI pair status changes to a status otherthan “PSUS” when snapshot data for the consistency group is being stored, the storagesystem cannot guarantee the consistency of the snapshot data.

Legend



N/A: Not applicable

SI pair operation

HTI pair status

COPY PAIR,PFULPSUS,PFUS SMPL(PD) RCPY PSUE

Create pair Yes Yes Yes Yes No Yes

Create and splitpair


Split pair Yes Yes Yes Yes No Yes

Normal Copy Yes Yes Yes Yes No Yes

Reverse Copy Yes Yes Yes Yes No Yes

Quick Restore No No No No No No

Suspendreplication


Delete pair Yes Yes Yes Yes Yes Yes

Legend




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The following table shows the SI pair operations that you can perform basedon the HTI pair status.

Even after snapshot data is stored, you can operate SI pairs. In this case,the storage system cannot maintain the consistency of the stored snapshotdata.

Because an HTI S-VOL uses the data in the P-VOL, you cannot perform theSI Quick Restore pair operation.

For more information about SI pair operations and pair statuses, see theHitachi ShadowImage® User Guide .

TrueCopy and Universal ReplicatorYou can share HTI P-VOLs with TC and UR pair volumes. The following tableslist the relationship between pair operations and status.

The following table shows the HTI pair operations you can perform based on

the TC/UR status.

SI pairoperation

HTI pair status

COPY PAIR,PFULPSUS,PFUS

SMPL(PD) RCPY PSUE

Create pair No No No No No No

Create and splitpair

No No No No No No

Split pair Yes Yes Yes Yes No Yes

Normal Copy Yes Yes Yes Yes No Yes

Reverse Copy Yes Yes Yes Yes No Yes

Quick Restore No No No No No No

Suspendreplication



Legend

Yes: You can perform the pair operationNo: You cannot perform the pair operation (the command is rejected)

Caution: The MU numbers used by HTI are 0 to 1,023, and they areassigned in the order of 3 to 1,023, followed by 0 to 2. On the other hand,the MU numbers used by SI are 0 to 2. Therefore, if HTI uses the MUnumber 0 to 2, HTI cannot share the volume with SI. To share a volumewith HTI and SI, delete the HTI pair of the MU number 0 to 2. Then, createSI pairs and HTI pairs.

HTI pairoperation

TC/UR status

COPY PAIR PSUS PSUE Suspending Deleting

Create pair Yes Yes Yes Yes Yes Yes




The following table shows the HTI pair operations you can perform based onthe TC/UR status.

The following table shows the TC/UR pair operations you can perform basedon the HTI status.

Store Snapshotdata


Restore pair No No Yes Yes No No

Delete Snapshotdata Yes Yes Yes Yes Yes Yes


Legend



HTI pairoperation

TC/UR status

COPY PAIR PSUS PSUE Suspending Deleting

HTI pair operation

TC/UR status

COPY PAIR PSUS PSUESSW

SSuspendin

g Deleting

Create pair Yes Yes Yes Yes Yes Yes Yes

Store Snapshot data No Yes Yes Yes Yes Yes Yes

Restore pair* No No No No No No No

Delete Snapshot data Yes Yes Yes Yes Yes Yes Yes

Delete pair Yes Yes Yes Yes Yes Yes Yes

* If you want to restore an HTI pair whose P-VOL is used as a TC or UR S-VOL, switchpair operations to the remote site using the horctakeover command.

Legend

Yes: You can perform the pair operationNo: You cannot perform the pair operation (the command is rejected)

TC/UR pairoperation

HTI status

COPY PAIR, PFUL PSUS, PFUS RCPY PSUE

Create pair Yes Yes Yes No Yes

Split pair Yes Yes Yes N/A Yes

Resynchronize pair Yes Yes Yes No YesDelete pair Yes Yes Yes Yes Yes

Switch to remotesite

Yes Yes Yes No Yes


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The following table shows the TC/UR pair operations you can perform basedon the HTI status.

Dynamic ProvisioningIf you use HTI, DP, and HDPz in one storage system, note the following:

• While the storage system is expanding the DP V-VOL capacity, youcannot create an HTI pair whose P-VOL is a DP V-VOL.

• Performing an HTI paircreate operation while zero pages are beingreclaimed (including reclamation by Writesame, Unmap command, orrebalancing) results in the zero-page operation being interrupted.

• HTI pair creation might be rejected if the Unmap command operation isin progress with system option mode 905 ON. Wait a while and thenretry the operation. If the operation still fails, set system option mode

905 to OFF and retry again.• You can use a DP volume size up to 4 TB (4,398,046,511,104 bytes) as

an HTI P-VOL.

When creating a DP V-VOL, if you specify TB, GB, or MB as the unit, youcannot create a volume of 4 TB (4,398,046,511,104 bytes). To create avolume of 4 TB (4,398,046,511,104 bytes), specify block as the unit.

Legend



N/A: Not applicable

TC/UR pairoperation

HTI status


TC/UR pairoperation

HTI status


Create pair No No No No No

Split pair Yes Yes Yes N/A Yes

Resynchronize pair Yes Yes Yes N/A Yes

Delete pair Yes Yes Yes N/A Yes

Switch to remote site Yes Yes Yes N/A Yes* If you want use a TC/UR S-VOL as an HTI P-VOL, first create the TC/UR pair thencreate the HTI pair.

For more information about TC pair operations and pair status, see the HitachiTrueCopy® User Guide . For more information about UR pair operations and pair status,see the Hitachi Universal Replicator User Guide .

Legend



N/A: Not applicable




The following table shows how the maximum LDEV capacity differsdepending on the unit you specify.

For more information about creating V-VOLs and about specifying LDEVcapacity and capacity unit, see Creating V-VOLs on page 3-5 .

Resource Partition ManagerYou can create an HTI pair regardless of whether the P-VOL and S-VOLs areassigned to the same resource group or different resource groups. However,the pool to be used must be assigned to the resource group where the P-VOL is assigned or to the resource group where creation of HTI pairs isallowed.

For more information about resource groups, see the Hitachi UnifiedStorage VM Block Module Provisioning Guide .

Software application acronyms and abbreviationsThis document uses the following acronyms and abbreviations for softwareproduct names:

• DP: Dynamic Provisioning

• HDPz: Dynamic Provisioning for Mainframe

• HUS VM: Hitachi Unified Storage VM

• UVM: Universal Volume Manager• SI: ShadowImage

• HTI: Hitachi Thin Image

• TC: TrueCopy

Unit specification Maximum LDEV capacity

TB 3.99

GB 4,095.99

MB 4,194,303.75

block 8,589,934,592


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2

Planning and design requirements 2–1


Planning and design requirements

This topic discusses planning and design requirements for HTI. Read thistopic before using HTI.

□ System requirements

□ Requirements for Thin Image operations



2–2 Planning and design requirements

System requirementsHTI operations require a HUS VM storage system with P-VOL and S-VOLs.HTI operations also require HTI and DP, which run on SN computers.

Requirements for Thin ImageTo use HTI, you must configure and set up the hardware and microcode anduse SN to make sure that a license key for DP is installed.

For more information about license keys and installation, see the HitachiStorage Navigator User Guide .

Installing Thin Image

The following procedure details how to install HTI:

1. Install DP, which is prerequisite software for HTI.

2. Install HTI.

Uninstalling Thin Image

The following procedure details how to uninstall HTI:

1. Release all HTI pairs.

2. Delete all pools.

3. Uninstall HTI.

Requirements for licensed capacityIf you use HTI, the capacity licensed for the HTI P-VOLs and pools is needed.The capacity of pools which are used for HTI is subtracted from the licensedcapacity for DP. Therefore, if you use HTI, secure the licensed capacity forDP more than the total capacity used for both DP and HTI.

The following table shows the HTI volumes and capacity calculated as theHTI usage. The total amount of these values must not exceed HTI licensecapacity.

For more information about licenses, see the Hitachi Storage Navigator UserGuide .

The intended volumes

The intendedcapacitySoftware application The kind ofvolumes

Normalvolume or DP-

VOL

HTI P-VOL Normal volume The volumecapacity

DP-VOL The pool capacityused by thevolume

Pool VOL Normal volume The volumecapacity


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Shared memory requirementsHTI requires dedicated shared memory for the HTI pair management area.The HTI pair management area is used to store information of HTI pairs.This area is automatically created when shared memory is added.

HTI requires at least 16 GB shared memory that consists of 2 sections. Ifyou are using HTI and you create a pool or V-VOL capacity, it is expandeddepending on the status of the shared memory installed. If you use a poolor V-VOL that has a capacity of 1,700TB or more, you must install SI/VM/DP Extension2, TI Extension .

To remove SI/VM/DP Extension2, TI Extension , first delete all of thepools for DP, HDT, and HTI.

If you want to install the shared memory, contact Hitachi Data Systemsservice representative.

Volume requirementsHTI requires the following types of volumes:

• P-VOLs• S-VOLs

• pool-VOLs

The following tables explain requirements for HTI P-VOLs, S-VOLs, andpool-VOLs. HTI uses DP pool-VOLs.

The following table shows the requirements for HTI P-VOLs.

The following table shows the requirements for HTI S-VOLs.

Item Requirement

Volume type Logical volumes (LDEVs).

You cannot specify the following volumesas HTI P-VOLs:• pool-VOLs

• HTI S-VOLs

• LUSE volumes

For more information about creating pairsusing other software applications, seeInteroperability with other software onpage 1-14 .

Emulation type OPEN-V

Maximum number of volumes 6,400

Note: This value can be increased

depending on your system configuration.Maximum number of HTI pairs See Calculating the number of Thin Image

pairs that you can create on page 2-7 .

Path definitions Required.

Maximum volume capacity 4TB




The following table shows the requirements for HTI pool-VOLs.

Item Requirement

Volume type V-VOLs

You cannot specify the following volumesas HTI S-VOLs:

• Volumes that are already used as S-VOLs

• Volumes that other softwareapplications are using for pairs ormigration plans

• LUSE volumes

For more information about calculating themaximum number of V-VOLs, seeCalculating the number of virtual volumesthat the storage system can create onpage 2-7 .

Emulation type OPEN-V

Note: If you use the CCI, Open-0V isshown.

Maximum number of volumes 12,800Note: This values can be increaseddepending on your system configuration.

Maximum number of pairs See Calculating the number of Thin Imagepairs that you can create on page 2-7 .

Path definitions Required


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Item Requirement

Volume type Logical volumes (LDEV)

The following configurations are recommended to maintainperformance levels:

• Do not mix normal volumes and pool-VOLs in a parity group.

• Make sure that pool-VOLs consist of LDEVs from multiple paritygroups.

• Assign different processor blade IDs* to LDEVs that make up pool-VOLs.

You cannot specify the following volumes as HTI pool-VOLs:

• Volumes whose volume status is other than “Normal” or “Normal(Quick Format)”. If the storage system is in the process of blockingor copying a volume, you cannot specify the volume.

• LUSE volumes

• Volumes that are already being used as HTI primary or S-VOLs.

• Volumes that are already contained in HTI, DP, or HDT pools.

• Volumes used as migration plans or pair volumes for anothersoftware application.

• Volumes with Protect or Read Only attribute, or the S-VOL Disableattribute setting (Data Retention Utility).

• Hitachi Cache Residency Manager (CRM) volumes.

• System disks

• Command devices

• HAM quorum disks

Also, note the following:

• You combine external pool-VOLs whose cache mode is enabled withthose whose cache mode is disabled in the same data pool.

• You cannot combine volumes in different resource groups in thesame data pool.

• You cannot use internal volumes and external volumes whosecache mode is disabled in the same data pool.

Emulationtype

OPEN-V

RAID level All RAID levels are supported.

Hard diskdrive type

You can use SAS and SSD.

If you use internal and external volumes, you can use pool-VOLs withdifferent drive types in the same pool. For best performance, use pool-VOLs with the same drive type in the same pool.

CLPR A data pool cannot contain pool-VOLs belonging to different cachelogical partitions (CLPRs). You cannot change CLPRs in the parity group

belonging to the pool-VOL.Maximumnumber ofpool-VOLs

You can add up to 1,024 pool-VOLs to a pool. You can create up to 128pools in a storage system.

If a volume is already contained in a pool, you cannot contain the pool-VOL in another pool. The number of available pools for HTI decreasesaccording to the number of DP pools (including HDT pools).

You can only add volumes that are assigned the same CLPRs to thesame pool. One RAID level is permitted in the same pool.




Consistency group requirementsThis topic lists the requirements for consistency groups.

The following table explains requirements for consistency groups.

Notes on consistency groups

Note the following in regards to consistency groups:

• You cannot define HTI pairs that share the same P-VOL in the sameconsistency group. If you do, the raidcom add snapshot CCI commandis rejected.

• Keep HTI pairs defined in consistency groups and pairs not defined inconsistency groups separate in groups that are defined by theconfiguration definition file for the CCI. These groups are notconsistency groups. If you mix these pairs, the pairsplit CCIcommand may finish abnormally. Also, if you store snapshot data fromthe P-VOL when HUS VM receives the pairsplit CCI command, thestorage system cannot guarantee the data.

• Specify only one consistency group for a group defined by theconfiguration definition file for the CCI.

Volumecapacity

8 GB to 4 TB

Path definition If you define unneeded paths to a volume, you cannot specify thevolume as a pool-VOL.

* For more information about how to change processor blade IDs, see the HitachiUnified Storage VM Block Module Provisioning Guide.

Item Requirement

Item Description

Consistency group number Assign a number from 0 to 255 when creating a pair. Ifyou do not assign a number, an unassigned number isautomatically assigned. Consistency group numbersappear in the following items in the GUI:

• Consistency Group tab of the Local Replications window

• Consistency Group Properties window

• Volume list in the Pair Operation window for SI

You can create up to 256 consistency groups in a storagesystem, with consistency groups for SI, and HTIcombined.

(For HTI only) You can also use consistency groupnumbers 128 to 255 (80 to FF).

Number of pairs You can create up to 8,192 pairs in a consistency group.You cannot mix SI and HTI pairs in a consistency group.HTI consistency groups can only contain HTI pairs.


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To create pairs using a group defined by the configuration definition filefor the CCI, and if a pair with a consistency group specified is alreadycreated in the group, the pair is added to the same consistency groupeven if you attempt to create a new pair in a different consistency group.

To specify multiple consistency groups, you must define the samenumber of groups using the configuration definition file for the CCI.

Snapshot group requirementsThe following table explains requirements for snapshot groups.

Requirements for Thin Image operationsThis section discusses points you should consider when performing HTI pairoperations.

Calculating the number of virtual volumes that the storage systemcan create

Use the following formula to calculate the maximum number of V-VOLs thatthe storage system can create:

The maximum number of V-VOLs = 12,800* - (The number of externalvolumes + The number of P-VOLs for HTI pairs)

* Your system configuration determines the maximum value in this formula.

Calculating the number of Thin Image pairs that you can createThe number of HTI pairs that you can create in a storage system dependson the shared memory capacity for V-VOL management areas, or thenumber of pair tables.

Use the following workflow to calculate the number of HTI pairs that you can

create:1. Calculate this number using the shared memory capacity for V-VOL

management areas, and the number of pair tables, respectively.

Item Description

Name The name of the snapshot group.

Character limit: 32 characters

Once you create a snapshot group, you cannot change itsname.

Maximum number • The maximum number of snapshot groups for onestorage system is 512.

• The maximum number of HTI pairs for one snapshot

group is 8,192.




2. Compare the three calculation results. The smallest of the two is themaximum number of HTI pairs that you can create in the storagesystem.

Calculating the number of Thin Image pairs based on pair tables

Pair tables contain information required for managing HTI pairs. Creation ofone HTI pair requires one each table. You can use up to 1,048,575 pairtables in a storage system.

Use the following formula to calculate the number of HTI pairs you cancreate:

1,048,575 - (the number of HTI pairs that were created)

For example, if the number of HTI pairs that were created is 30,000, usethe following formula to calculate the number of HTI pairs you can create:

1,048,575 - 30,000 = 1,018,575

The calculation result shows that you can create up to 1,018,575 HTI pairs.

An HTI pair consists of one P-VOL and up to 1,024 V-VOLs.

Calculating the number of Thin Image pairs based on the snapshotestimated manageable capacity

To view the snapshot estimated manageable capacity, in the StorageSystems tree, click Replications > Local Replications .

To calculate the number of HTI pairs you can create, use the followingformula:

The number of HTI pairs you can create = the number of Snapshotestimated manageable capacity / the Snapshot management capacityper one P-VOL

To calculate the Snapshot management capacity per P-VOL, use thefollowing formula:

The Snapshot management capacity per P-VOL = (the P-VOL capacityof HTI pairs [TB] / 2.6 [TB]) * 3,024 [GB] + (168GB * 2 (consumedshared memory))

Calculating the number of Thin Image pairs workflowUse the following process to calculate the number of HTI pairs based on thenumber of cache management devices:

1. View the number of cache management devices. Click Action > ViewManagement Resource Usage .

2. Calculate the number of HTI pairs that you can create. Use the followingformula to calculate the number:

Note: If DP volumes are already created in the storage system, youcan create an even smaller number of HTI pairs.


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(the Number of cache management devices / the P-VOL capacityof HTI pairs [TB]) / 2.6 [TB]

Calculating the number of cache management devicesThis section explains the number of cache management devices that arerequired to perform HTI pair operations.

Cache management devices are the unit for controlling the cache inassociation with LDEVs. Each LDEV requires at least one cache managementdevice.

You can manage up to 65,280 cache management devices in a system. Usethe View Management Resource Usage window to view the number ofcache management devices.

For more information about LDEVs and cache management devices requiredfor DP-VOLs, see the Hitachi Unified Storage VM Block Module ProvisioningGuide .

The number of cache management devices required for Thin Image pair

operationsHTI assigns 4,096 of the 8,192 cache management devices. 8,192 cachemanagement devices must be available to create an HTI pool for the firsttime. 4,097 or more cache management devices must be available to createan HTI pair for a volume for the first time.

Use the following formula to calculate the number of cache managementdevices you need to create an HTI pair for a volume for the first time:

ceil(Size of P-VOL ÷ 2.6) (in terabytes)

If the amount of pool usage for the P-VOL exceeds 70 percent of the totalcapacity of the cache management devices reserved for the P-VOL, you

must reserve an additional cache management device. Up to 256 cachemanagement devices are required for a P-VOL.

Effects on I/O performance of the storage systemIf you perform HTI restore operations when the workload on the storagesystem is high, I/O performance of host servers can decline becausereplication processes for the P-VOLs are triggered. You can use the copythreshold option to lower the workload on the storage system.

For more information about using the copy threshold option, see Copythreshold option on page 1-13 .

Notes on assigning the pool capacityYou can calculate the capacity of which to store snapshot data in the poolusing the following formula:

Pool capacity = the total capacity of pool-VOLs in the pool -the capacity of V-VOL management areas




The capacity of V-VOL management areas is 3% of the pool capacity. If thepool capacity is insufficient, the status of HTI pairs may change to “PSUE”.Therefore, you must do the following:

• Estimate the capacity of snapshot data to be copied to the pool.

• Assign the pool capacity based on the estimate. If the capacity ofsnapshot data to be copied to the pool varies hour by hour, make surethat the largest capacity is your pool capacity.

If snapshot data is copied to the pool, the pool capacity is always consumedin units of 42 megabytes. Even if snapshot data is smaller than 42megabytes, at least 42 megabytes of pool capacity is needed.

It is recommended the capacity of a pool-VOL should be multiples of 42megabytes. If the capacity of a volume specified as a pool-VOL is notmultiples of 42 megabytes, the fraction of less than 42 megabytes istruncated.

Estimating the capacity of snapshot data to be copied to the pool

To decide the capacity of pools, estimate the capacity of snapshot data tobe copied.

The capacity of snapshot data to be copied equals to the capacity of datawritten to the same area in the P-VOL during the period from when snapshotdata is stored to when the snapshot data is deleted.

If multiple snapshot data are stored, the data may be shared in a pool. Ifthere are the snapshot data containing the shared data, you can release HTIpairs, but you cannot delete the snapshot data from the pool. If you releaseall HTI pairs that have snapshot data containing the shared data, thesnapshot data are also deleted from the pool.

To create a backup data using HTI, store snapshot data then use an S-VOL.In this case, the target for the backup is only the areas where the snapshotdata is stored. You can create backup copies even when the pool capacity issmall. While you are creating a backup copy, a large amount of data is readfrom the S-VOL. This may increase the accesses to the P-VOL and degradethe host I/O performance.

Although the pool capacity is decided according to the estimation, if the poolcapacity exceeds the threshold, address the issue.

For more information about addressing exceeding pool capacity thresholdissues, see General troubleshooting on page 6-2 .

Using external volumes as pool-VOLs

You can use UVM to connect your HUS VM storage system to other storagesystems. In UVM terminology, your HUS VM storage system is referred toas a local storage system, and the other storage systems are referred to asexternal storage systems. Volumes in external storage systems are referredto as external volumes. Volumes in a local storage system are referred toas internal volumes.


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If UVM is installed, you can use external and internal volumes as pool-VOLs.However, if you use external volumes, the likelihood of failure increases andthe disaster recovery is more complex and challenging.

If you use external volumes as pool-VOLs, use one pool for one externalstorage system to minimize adverse effect of failure.

You can use multiple external volumes as pool-VOLs in a pool. However, ifexternal volumes are used, it increases the likelihood of a failure. For

example, the pool might be blocked. If the external pool-VOLs are blockeddue to a failure, the pool is also blocked.

For more information about how to restore a blocked pool, see Blocked poolrecovery workflow on page 6-5 .

For more information about external storage systems and disaster recoverymethods for external volumes, see the Hitachi Universal Volume ManagerUser Guide .


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3

Performing configuration operations 3–1


Performing configuration operations

This topic describes creating pools, creating V-VOLs, and settings of thecommand device for configuring HTI.

□ Configuration workflow

□ Creating pools

□ Creating V-VOLs

□ Setting up command devices



3–2 Performing configuration operations

Configuration workflowUse the following configuration operations workflow to configure HTI. Thefollowing image shows the workflow.

You must create a V-VOL management area in the shared memory beforeyou create pools. The V-VOL management area is created when additional

shared memory is installed. For more information about the additionalshared memory, contact the Hitachi Data Systems Support Center.

After you have create the HTI pairs and acquired the snapshot data, you canmaintain the HTI pair status. Delete any unneeded snapshot data or HTIpairs. Releasing HTI pairs deletes the snapshot data, which are acquiredwith the HTI pair, from the pool.

When the recovery operation is performed after a failure occurred, you canwrite snapshot data over the P-VOL. While recovering an HTI pair, youcannot recover other HTI pairs.

For more information about operations on HTI pairs and pair statuses, seePair operations on page 4-1 .

Creating poolsThis topic describes how to create data pools using SN.

If you create pools, the new pool-VOL with system area is set automaticallyaccording to the priority of hard disk drive types explained in the followingtable.

Priority Hard disk drive type

1 SAS7.2K

2 SAS10K3 SAS15K

4 SSD

5 External volume


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Performing configuration operations 3–3


If plural pool-VOLs of the same hard disk drive type exist, the priority ofthem is determined according to the internal index information of thestorage system.

Related topics• Create Pools wizard in Hitachi Unified Storage VM Block Module

Provisioning Guide

1. In the Storage Systems tree, select Pools .2. In the Pools window, click Create Pools .

3. In the Create Pools window, complete the following and then clickOptions :

For Pool Type , select Thin Image .

Required: Yes

Select a pool-VOL by completing the following:

- For Drive Type/RPM , select your system's data drive type andRPM.

Values: External Storage

Maximum volume: 3

- For RAID Level , select the system's RAID level.

Values: Mixed

4. Click Select Pool VOLs .

5. In the Select Pool Volumes window, complete the following and thenclick OK :

For Pool Name , type the prefix and initial number for the pool name.Required: Yes

Character limit: 32

- For Prefix , type alphanumeric characters as the prefix. Casesensitive: Yes

- For Initial Number , type a number.

Digit limit: 9

The information in the Selected Pool Volumes table is applied toTotal Selected Pool Volumes and Total Selected Capacity .

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