Download pdf - Hitachi Virtual Storage Platform G1000 - Hitachi Data … · Hitachi Virtual Storage Platform G1000 Provisioning Guide for Open Systems Hitachi Data Retention Utility Hitachi Dynamic

Hitachi Virtual Storage Platform G1000Provisioning Guide for Open Systems

Hitachi Data Retention Utility

Hitachi Dynamic Provisioning

Hitachi Dynamic Tiering

Hitachi LUN Manager

Hitachi Resource Partition Manager

MK-92RD8014-10

June 2016

2014, 2016 Hitachi, Ltd. All rights reserved.

No part of this publication may be reproduced or transmitted in any form or by any means, electronicor mechanical, including copying and recording, or stored in a database or retrieval system forcommercial purposes without the express written permission of Hitachi, Ltd., or Hitachi Data SystemsCorporation (collectively Hitachi). Licensee may make copies of the Materials provided that any suchcopy is: (i) created as an essential step in utilization of the Software as licensed and is used in noother manner; or (ii) used for archival purposes. Licensee may not make any other copies of theMaterials. Materials mean text, data, photographs, graphics, audio, video and documents.

Hitachi reserves the right to make changes to this Material at any time without notice and assumesno responsibility for its use. The Materials contain the most current information available at the timeof publication.

Some of the features described in the Materials might not be currently available. Refer to the mostrecent product announcement for information about feature and product availability, or contactHitachi Data Systems Corporation at https://support.hds.com/en_us/contact-us.html.

Notice: Hitachi products and services can be ordered only under the terms and conditions of theapplicable Hitachi agreements. The use of Hitachi products is governed by the terms of youragreements with Hitachi Data Systems Corporation.

By using this software, you agree that you are responsible for:1. Acquiring the relevant consents as may be required under local privacy laws or otherwise from

authorized employees and other individuals to access relevant data; and2. Verifying that data continues to be held, retrieved, deleted, or otherwise processed in

accordance with relevant laws.

Notice on Export Controls. The technical data and technology inherent in this Document may besubject to U.S. export control laws, including the U.S. Export Administration Act and its associatedregulations, and may be subject to export or import regulations in other countries. Reader agrees tocomply strictly with all such regulations and acknowledges that Reader has the responsibility to obtainlicenses to export, re-export, or import the Document and any Compliant Products.

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

AIX, AS/400e, DB2, Domino, DS6000, DS8000, Enterprise Storage Server, eServer, FICON,FlashCopy, IBM, Lotus, MVS, OS/390, PowerPC, RS/6000, S/390, System z9, System z10, Tivoli,z/OS, z9, z10, z13, z/VM, and z/VSE are registered trademarks or trademarks of InternationalBusiness Machines Corporation.

Active Directory, ActiveX, Bing, Excel, Hyper-V, Internet Explorer, the Internet Explorer logo,Microsoft, the Microsoft Corporate Logo, MS-DOS, Outlook, PowerPoint, SharePoint, Silverlight,SmartScreen, SQL Server, Visual Basic, Visual C++, Visual Studio, Windows, the Windows logo,Windows Azure, Windows PowerShell, Windows Server, the Windows start button, and Windows Vistaare registered trademarks or trademarks of Microsoft Corporation. Microsoft product screen shots arereprinted with permission from Microsoft Corporation.

All other trademarks, service marks, and company names in this document or website are propertiesof their respective owners.

2Hitachi Virtual Storage Platform G1000 Provisioning Guide for Open Systems

https://support.hds.com/en_us/contact-us.html

Contents

Preface............................................................................................... 13Intended audience................................................................................................. 14Product version......................................................................................................14Release notes........................................................................................................ 14Changes in this revision..........................................................................................14Related documents.................................................................................................14Document conventions........................................................................................... 15Conventions for storage capacity values...................................................................16Accessing product documentation........................................................................... 17Getting help...........................................................................................................17Comments.............................................................................................................17

1 Introduction to provisioning..................................................................19About provisioning................................................................................................. 20Key terms..............................................................................................................20Basic provisioning...................................................................................................21

Fixed-sized provisioning.................................................................................... 21Overview of fixed-sized provisioning............................................................. 21Disadvantages............................................................................................ 23When to use fixed-sized provisioning............................................................ 23

Custom-sized provisioning................................................................................. 23Overview of custom-sized provisioning..........................................................23When to use custom-sized provisioning.........................................................24

Basic provisioning workflow...............................................................................24Thin provisioning....................................................................................................25

Dynamic Provisioning........................................................................................25About Dynamic Provisioning.........................................................................25When to use Dynamic Provisioning............................................................... 26Dynamic Provisioning advantages.................................................................26DP-VOL with data direct mapping attribute....................................................27Dynamic Provisioning advantage example..................................................... 30Dynamic Provisioning high-level workflow..................................................... 31Pools comprised of pool volumes carved from accelerated compression-enabledparity groups.............................................................................................. 31

Data retention strategies...................................................................................34


Dynamic Tiering .............................................................................................. 34Dynamic Tiering..........................................................................................34Overview of tiers.........................................................................................35When to use Dynamic Tiering...................................................................... 36

Active flash...................................................................................................... 36Requirements........................................................................................................ 38

System requirements........................................................................................ 38Shared memory requirements............................................................................39

About cache management devices...........................................................................40Calculating the number of cache management devices required for DP-VOLs........ 40Maximum capacity of cache management devices...............................................40Calculating the number of cache management devices required by a volume that isnot a DP-VOL................................................................................................... 41Viewing the number of cache management devices.............................................41

2 Managing virtual storage machine resources..........................................43About virtual storage machines and virtualized resources.......................................... 44Provisioning operations for resources in a virtual storage machine............................. 45Pair operations with virtual storage machine pairs.................................................... 45Software operations for resources in a virtual storage machine..................................47Editing virtualization management settings...............................................................47

3 Configuring resource groups.................................................................51When to use resource groups .................................................................................52System configuration using resource groups.............................................................52

Meta_resource..................................................................................................53Resource lock...................................................................................................53Resource group assignments............................................................................. 53User groups..................................................................................................... 54

Resource groups examples..................................................................................... 54Example of resource groups sharing a port.........................................................54Example of resource groups not sharing ports.................................................... 56

Resource group rules, restrictions, and guidelines.....................................................58Using Resource Partition Manager and other VSP G1000 products..............................58

Dynamic Provisioning........................................................................................59Encryption License Key......................................................................................59LUN Manager................................................................................................... 60Performance Monitor.........................................................................................62ShadowImage.................................................................................................. 62Thin Image...................................................................................................... 63TrueCopy......................................................................................................... 63Global-active device.......................................................................................... 64Universal Replicator.......................................................................................... 65Universal Volume Manager................................................................................ 66Open Volume Management................................................................................67Virtual Partition Manager...................................................................................68Volume Shredder.............................................................................................. 69Server Priority Manager.....................................................................................69

Managing resource groups......................................................................................69Creating resource groups.................................................................................. 70


Editing resource groups.....................................................................................70Deleting resource groups...................................................................................71

4 Configuring custom-sized provisioning...................................................73Virtual LUN functions..............................................................................................74Virtual LUN specifications........................................................................................74

Virtual LUN specifications for open systems........................................................ 74CV capacity by emulation type for open systems................................................. 75

Virtual LUN size calculations....................................................................................75Calculating OPEN-V volume size (CV capacity unit is MB)..................................... 76Calculating OPEN-V volume size (CV capacity unit is blocks).................................77Calculating fixed-size open-systems volume size (CV capacity unit is MB)..............77Calculating fixed-size open-systems volume size (CV capacity unit is blocks)......... 78Management area capacity of an open-systems volume.......................................79Boundary values for RAID levels........................................................................ 79Capacity of a slot..............................................................................................79Configuring volumes in a parity group ............................................................... 79

Enabling accelerated compression........................................................................... 80Disabling accelerated compression.......................................................................... 82Configuration of interleaved parity groups................................................................83SSID requirements................................................................................................. 84Creating and deleting volumes................................................................................ 84

About creating volumes.....................................................................................84Notes on performing quick formats.................................................................... 85Creating volumes..............................................................................................86Create Volumes dialog box................................................................................ 87About shredding volume data............................................................................ 89Shredding volume data..................................................................................... 89About deleting unallocated volumes................................................................... 90Deleting unallocated volumes............................................................................ 90

Create LDEV function............................................................................................. 91Creating an LDEV............................................................................................. 91Finding an LDEV ID...........................................................................................96Finding an LDEV SSID ......................................................................................96Editing an LDEV SSID ...................................................................................... 97Changing LDEV settings.................................................................................... 97Removing an LDEV to be registered................................................................... 98

Blocking and restoring LDEVs..................................................................................99Blocking LDEVs.................................................................................................99Blocking LDEVs in a parity group........................................................................99Block LDEVs window....................................................................................... 100Restoring blocked LDEVs................................................................................. 101Restoring blocked LDEVs in a parity group........................................................ 102Restore LDEVs window....................................................................................102

Formatting LDEVs.................................................................................................104About formatting LDEVs.................................................................................. 104Storage system operation when LDEVs are formatted........................................104Quick Format function..................................................................................... 104Quick Format specifications............................................................................. 106Formatting LDEVs in a Windows environment................................................... 107Formatting a specific LDEV.............................................................................. 107


Formatting all LDEVs in a parity group..............................................................108Format LDEVs wizard...................................................................................... 108

Format LDEVs window............................................................................... 108Format LDEVs confirmation window............................................................109

Assigning an MP blade..........................................................................................111Guidelines for changing the MP blade assigned to an LDEV................................ 111Assigning an MP blade to a resource................................................................ 111Changing the MP blade assigned to an LDEV.....................................................112Changing the ALUA mode setting of LDEV........................................................ 113Components window.......................................................................................113DKC: MP Blades tab........................................................................................ 115Assign MP Blade wizard...................................................................................116

Assign MP Blade window............................................................................116Assign MP Blade confirmation window.........................................................117

Edit MP Blades wizard..................................................................................... 119Edit MP Blades window.............................................................................. 119Edit MP Blades confirmation window...........................................................120

Viewing LDEVs of ALUs or SLU attribution.............................................................. 120

5 Configuring thin provisioning ............................................................. 123Dynamic Provisioning overview..............................................................................125Dynamic Tiering overview..................................................................................... 125Active flash overview............................................................................................ 125Thin provisioning requirements..............................................................................125

License requirements...................................................................................... 125Pool requirements...........................................................................................126Pool-VOL requirements....................................................................................128DP-VOL requirements......................................................................................130Requirements for increasing DP-VOL capacity................................................... 130Estimating the required capacity of pool-VOLs with system area in the pool withdata direct mapping enabled............................................................................131Operating system and file system capacity........................................................132

Using Dynamic Provisioning or Dynamic Tiering or active flash with other products forVSP G1000...........................................................................................................134

Interoperability of DP-VOLs and pool-VOLs....................................................... 134ShadowImage pair status for reclaiming zero pages.......................................... 137TrueCopy........................................................................................................137Universal Replicator........................................................................................ 138ShadowImage................................................................................................ 139Thin Image.................................................................................................... 140Virtual Partition Manager CLPR setting..............................................................140Volume Migration............................................................................................140Resource Partition Manager............................................................................. 140

Dynamic Provisioning workflow............................................................................. 140Migrating V-VOL data...................................................................................... 142Restoring backup data.....................................................................................142

Dynamic Tiering and active flash........................................................................... 142About tiered storage....................................................................................... 142Tier monitoring and data relocation..................................................................143Multi-tier pool.................................................................................................143Tier monitoring and relocation cycles................................................................144


Auto execution mode.................................................................................144Manual execution mode............................................................................. 146

Tier relocation workflow.................................................................................. 148Tier relocation rules, restrictions, and guidelines............................................... 151Buffer area of a tier.........................................................................................155Setting external volumes for each tier.............................................................. 156Example of required Dynamic Tiering cache capacity......................................... 157Execution modes for tier relocation.................................................................. 157

Execution modes when using Hitachi Device Manager - Storage Navigator ....158Viewing monitor and tier relocation information using HDvM - SN................. 159Execution modes when using Command Control Interface............................ 161Viewing monitor and tier relocation information using CCI............................ 162

Relocation speed.............................................................................................162Monitoring modes........................................................................................... 163Cautions when using monitoring modes............................................................164Notes on performing monitoring...................................................................... 165Downloading the tier relocation log file.............................................................165Tier relocation log file contents........................................................................ 166Tiering policy..................................................................................................171

Custom Policies......................................................................................... 171Tiering policy examples..............................................................................172Setting tiering policy on a DP-VOL.............................................................. 174Tiering policy levels................................................................................... 174Viewing the tiering policy in the performance graph.....................................175Reserving tier capacity when setting a tiering policy.....................................176Example of reserving tier capacity.............................................................. 177Notes on tiering policy settings...................................................................179New page assignment tier..........................................................................181Relocation priority..................................................................................... 182Assignment tier when pool-VOLs are deleted............................................... 183Formatted pool capacity.............................................................................184Rebalancing the usage level among parity groups........................................185Execution mode settings and tiering policy.................................................. 186

Functions overview for active flash and Dynamic Tiering....................................187Relocating pages whose latest I/Os frequency is suddenly high by active flash.... 189Dynamic Tiering workflow............................................................................... 190Active flash workflow...................................................................................... 192

Thresholds...........................................................................................................194Pool utilization thresholds................................................................................ 194Pool subscription limit..................................................................................... 195Monitoring total DP-VOL subscription for a pool.................................................196

Working with pools...............................................................................................197About pools....................................................................................................197About pool-VOLs.............................................................................................197Pool status..................................................................................................... 198Creating pools................................................................................................ 199Deleting a pool............................................................................................... 199Configuring a Dynamic Tiering pool for use by active flash.................................200

Working with DP-VOLs..........................................................................................201About DP-VOLs...............................................................................................201Relationship between a pool and DP-VOLs........................................................ 202

Virtualizing storage capacity (DP/HDT)...................................................................202


About virtualizing storage capacity................................................................... 202Creating a DP pool..........................................................................................204Create Pool dialog box.....................................................................................206Verifying DP pool information...........................................................................210Expanding DP pools........................................................................................ 211Shrinking a DP pool.........................................................................................213Modifying DP pool settings...............................................................................214Deleting DP pools........................................................................................... 214Expanding DP volumes....................................................................................215Reclaiming zero pages.....................................................................................215

Virtualizing storage tiers (HDT)..............................................................................215About virtualizing storage tiers.........................................................................216Manually starting or stopping the monitoring of HDT pools................................ 218Manually starting or stopping the tier relocation of an HDT pool.........................219Scheduling monitoring and tier relocation of HDT pools..................................... 219Editing tier relocation for HDT volumes.............................................................220Applying a tiering policy to HDT volumes.......................................................... 220Customizing a tiering policy for HDT volumes....................................................221Changing a tiering policy name........................................................................ 222Notes on data placement profiles for HDT volumes............................................223Creating a data placement profile for HDT volumes........................................... 224Updating a data placement profile for HDT volumes.......................................... 225Editing a data placement profile for HDT volumes............................................. 226Applying a data placement profile for HDT volumes...........................................226Scheduling data placement profiles for HDT volumes.........................................227Editing an external LDEV tiering rank for an HDT pool....................................... 228

Monitoring capacity and performance.....................................................................228Monitoring pool capacity..................................................................................229Monitoring pool usage levels............................................................................229Monitoring performance.................................................................................. 229Managing I/O usage rates example.................................................................. 230Tuning with Dynamic Tiering............................................................................231Improving performance by monitoring pools..................................................... 231

Working with SIMs .............................................................................................. 234About SIMs.....................................................................................................234SIM reference codes....................................................................................... 234Automatic completion of a SIM ....................................................................... 237Manually completing a SIM..............................................................................238Complete SIMs window................................................................................... 239

Enabling data direct mapping for external volumes, pools, and DP-VOLs.................. 240Creating external volumes with data direct mapping enabled............................. 240Creating pools with data direct mapping enabled.............................................. 242Creating DP-VOLs with data direct mapping enabled......................................... 244Editing the data direct mapping attribute for a pool...........................................245

6 Configuring access attributes.............................................................. 247About access attributes.........................................................................................248

Access attribute requirements..........................................................................248Access attributes and permitted operations.......................................................249Access attribute restrictions............................................................................. 249Access attributes workflow.............................................................................. 250


Working with access attributes.............................................................................. 250Assigning an access attribute to a volume.........................................................250Changing an access attribute to read-only or protect......................................... 251Changing an access attribute to read/write....................................................... 252Enabling or disabling the expiration lock........................................................... 253Disabling an S-VOL......................................................................................... 254Reserving volumes..........................................................................................255Data Retention window................................................................................... 256Error Detail dialog box.....................................................................................258

7 Managing logical volumes...................................................................261LUN Manager overview......................................................................................... 262

LUN Manager Function.................................................................................... 262LUN Manager operations................................................................................. 262Fibre channel operations................................................................................. 262LUN Manager rules, restrictions, and guidelines for managing LUNs....................264

Allocating and unallocating volumes.......................................................................265About allocating volumes.................................................................................265Volume allocation methods.............................................................................. 267Prerequisites for allocating volumes..................................................................268Allocating volumes from general tasks.............................................................. 268Allocating volumes to selected hosts................................................................ 269Allocating volumes to selected file servers........................................................ 270Allocating selected volumes to hosts................................................................ 271Allocating volumes to clustered hosts............................................................... 272Allocating volumes by using a keyword search.................................................. 273Allocating volumes by using a criteria search.................................................... 274Allocating volumes by using existing volume settings.........................................275Allocate Volumes dialog box.............................................................................276About clustered-host storage........................................................................... 285Creating clustered-host storage........................................................................286About unallocating volumes............................................................................. 288Unallocating volumes from hosts......................................................................288Unallocating volumes from file servers..............................................................289Unallocate volumes dialog box......................................................................... 290

Managing logical units workflow............................................................................ 292Configuring Fibre Channel ports.............................................................................292

Setting the data transfer speed on a Fibre Channel port.....................................292Combination of data-transfer speed and connection type................................... 294Setting the Fibre Channel port address............................................................. 294Addresses for Fibre Channel ports.................................................................... 295Setting the fabric switch.................................................................................. 296Fibre Channel topology....................................................................................297Example of FC-AL and point-to-point topology...................................................298Setting the Fibre Channel topology...................................................................298

Overview for iSCSI............................................................................................... 299Network configuration for iSCSI....................................................................... 299

Managing hosts....................................................................................................302Configure hosts workflow................................................................................ 302Host modes for host groups.............................................................................302Host mode options..........................................................................................303


Find WWN of the host bus adapter...................................................................307Finding a WWN on Windows...................................................................... 307Finding a WWN on Oracle Solaris.............................................................308Finding a WWN on AIX, IRIX, or Sequent....................................................309Finding WWN for HP-UX.............................................................................309

Changing settings for a manually registered host.............................................. 310Changing settings for a host registered by using Device Manager agent..............310Editing the host mode and host mode options...................................................312Editing a WWN nickname................................................................................ 313Changing HBA iSCSI name or nickname of a host bus adapter........................... 314Changing iSCSI target setting.......................................................................... 315Removing hosts from iSCSI targets.................................................................. 316Deleting an iSCSI target.................................................................................. 317Deleting login iSCSI names..............................................................................318Adding a selected host to a host group.............................................................318Adding a host to the selected iSCSI target........................................................ 319Setting T10 PI mode to the port.......................................................................320Deleting logical groups.................................................................................... 321Creating iSCSI targets and registering hosts in the iSCSI target..........................321Editing iSCSI port settings............................................................................... 323Adding CHAP users......................................................................................... 324Editing CHAP users......................................................................................... 325Removing CHAP users..................................................................................... 326Removing target CHAP users........................................................................... 326

Managing LUN Paths.............................................................................................327About LUN path management..........................................................................327Editing LUN paths........................................................................................... 328Editing LUN paths when exchanging a failed HBA..............................................330Editing LUN paths when adding or exchanging an HBA...................................... 331Removing LUN paths after adding an HBA........................................................ 332

Releasing LUN reservation by host.........................................................................333Configuring LUN security.......................................................................................333

LUN security on ports......................................................................................334Examples of enabling and disabling LUN security on ports................................. 334Enabling LUN security on a port....................................................................... 335Disabling LUN security on a port...................................................................... 336

Setting Fibre Channel authentication......................................................................337User authentication.........................................................................................337

Settings for authentication of hosts.............................................................338Settings for authentication of ports (required if performing mutualauthentication)..........................................................................................339

Host and host group authentication..................................................................339Example of authenticating hosts in a Fibre Channel environment.................. 341Port settings and connection results............................................................343

fabric switch authentication............................................................................. 343fabric switch settings and connection results.....................................................345Mutual authentication of ports......................................................................... 346Fibre Channel authentication........................................................................... 346

Enabling or disabling host authentication on a host group............................ 346Registering host user information............................................................... 347Changing host user information registered on a host group.......................... 348Deleting host user information....................................................................349


Registering user information for a host group (for mutual authentication)......350Clearing user information from a host group................................................351

Fibre channel port authentication.....................................................................351Setting Fibre Channel port authentication....................................................351

Registering user information on a Fibre Channel port.........................................352Registering user information on a fabric switch................................................. 353Clearing fabric switch user information............................................................. 354Setting the fabric switch authentication mode................................................... 355Enabling or disabling fabric switch authentication..............................................356

8 Configuring VASA integrated storage systems...................................... 357Creating LDEVs of ALU attribution..........................................................................359Viewing LDEVs of ALUs or SLU attribution.............................................................. 360Unbinding LDEVs of SLUs attribution......................................................................361

9 Troubleshooting................................................................................. 363Troubleshooting Virtual LUN.................................................................................. 364Troubleshooting Dynamic Provisioning................................................................... 364Troubleshooting Data Retention Utility................................................................... 368

Data Retention Utility troubleshooting instructions.............................................368Troubleshooting provisioning while using Command Control Interface...................... 368

Errors when operating CCI (Dynamic Provisioning, SSB1: 0x2e31/0xb96d) .........369Errors when operating CCI (Data Retention Utility, SSB1:2E31/B9BF/B9BD).........371

Calling Hitachi Data Systems customer support.......................................................371

A CCI command reference..................................................................... 373Hitachi Device Manager - Storage Navigator tasks and CCI command list................. 374

B Guidelines for pools when accelerated compression is enabled.............. 377Checking whether accelerated compression can be enabled.....................................378Estimating required FMC capacity.......................................................................... 378

Hitachi Accelerated Flash Compression Estimator Tool....................................... 378Workflow for estimating FMC capacity needed for a new pool.............................379Workflow for estimating FMC capacity to expand an existing pool.......................382

Workflow for creating parity groups, LDEVs, and pools............................................383Monitoring the pool capacity................................................................................. 386Workflow for estimating FMC capacity needed when pool capacity is insufficient....... 386Workflow for disabling accelerated compression on a parity group........................... 387

Glossary............................................................................................ 389

Index................................................................................................ 399


PrefaceThis document describes and provides instructions for using the provisioningsoftware to configure and perform operations on Hitachi Virtual StoragePlatform G1000 systems. Provisioning software includes Hitachi DynamicProvisioning, Hitachi Dynamic Tiering, Hitachi LUN Manager, Hitachi VirtualLUN, and Hitachi Data Retention Utility.

Please read this document carefully to understand how to use these products,and maintain a copy for your reference.

Intended audience

Product version

Release notes

Changes in this revision

Related documents

Document conventions

Conventions for storage capacity values

Accessing product documentation

Getting help

Comments

Preface 13Hitachi Virtual Storage Platform G1000 Provisioning Guide for Open Systems

Intended audienceThis document is intended for system administrators, Hitachi Data Systemsrepresentatives, and authorized service providers who install, configure, andoperate Hitachi Virtual Storage Platform G1000 storage systems.

Readers of this document should be familiar with the following: Data processing and RAID storage systems and their basic functions. The Hitachi Virtual Storage Platform G1000 storage system and the Hitachi

Virtual Storage Platform G1000 Product Overview. The Hitachi Command Suite software and Hitachi Device Manager -

Storage Navigator Hitachi Command Suite User Guide. The concepts and functionality of storage provisioning operations.

Product versionThis document revision applies to: VSP G1000 microcode 80-04-2x or later. SVOS 6.4.1 or later

Release notesRead the release notes before installing and using this product. They maycontain requirements or restrictions that are not fully described in thisdocument or updates or corrections to this document. Release notes areavailable on Hitachi Data Systems Support Connect: https://support.hds.com/en_us/documents.html.

Changes in this revision Added information about Fibre Channel authentication. See Setting Fibre

Channel authentication on page 337.

Related documentsThe documents below are referenced in this document or contain moreinformation about the features described in this document.

Hitachi Virtual Storage Platform G1000 documents: Hitachi Virtual Storage Platform G1000 Product Overview, MK-92RD8051 Hitachi Virtual Storage Platform G1000 Hardware Guide, MK-92RD8007 Hitachi Command Suite System Requirements, MK-92HC209 Hitachi Command Suite User Guide, MK-90HC172

14 PrefaceHitachi Virtual Storage Platform G1000 Provisioning Guide for Open Systems

https://support.hds.com/en_us/documents.htmlhttps://support.hds.com/en_us/documents.html

Hitachi Command Suite Configuration Reference Guide, MK-90HC1725 Hitachi Command Suite Messages, MK-90HC178 Hitachi Virtual Storage Platform G1000 Performance Guide, MK-92RD8012 Hitachi SNMP Agent User Guide, MK-92RD8015 Hitachi TrueCopy User Guide, MK-92RD8019 Hitachi ShadowImage User Guide, MK-92RD8021 Hitachi Universal Replicator User Guide, MK-92RD8023 Hitachi Universal Volume Manager User Guide, MK-92RD8024 Hitachi Volume Shredder User Guide, MK-92RD8025

For a list of all documents for the Hitachi Virtual Storage Platform G1000storage system, see the Hitachi Virtual Storage Platform G1000 ProductOverview.

Document conventionsThis document uses the following typographic conventions:

Convention Description

Bold Indicates text in a window, including window titles, menus, menu options,buttons, fields, and labels. Example:Click OK.

Indicates emphasized words in list items.

Italic Indicates a document title or emphasized words in text. Indicates a variable, which is a placeholder for actual text provided by the

user or for output by the system. Example:pairdisplay -g group(For exceptions to this convention for variables, see the entry for anglebrackets.)

Monospace Indicates text that is displayed on screen or entered by the user. Example:pairdisplay -g oradb

< > angle brackets Indicates variables in the following scenarios: Variables are not clearly separated from the surrounding text or from

other variables. Example:Status-.csv

Variables in headings.

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

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

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

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

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

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


Icon Label Description

Note Calls attention to important or additional information.

Tip Provides helpful information, guidelines, or suggestions for performingtasks more effectively.

Caution Warns the user of adverse conditions and/or consequences (forexample, disruptive operations, data loss, or a system crash).

WARNING Warns the user of a hazardous situation which, if not avoided, couldresult in death or serious injury.

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

Physical capacity unit Value

1 kilobyte (KB) 1,000 (10 3) bytes

1 megabyte (MB) 1,000 KB or 1,0002 bytes

1 gigabyte (GB) 1,000 MB or 1,0003 bytes

1 terabyte (TB) 1,000 GB or 1,0004 bytes

1 petabyte (PB) 1,000 TB or 1,0005 bytes

1 exabyte (EB) 1,000 PB or 1,0006 bytes

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

Logical capacity unit Value

1 block 512 bytes

1 cylinder Mainframe: 870 KB

Open-systems: OPEN-V: 960 KB Others: 720 KB

1 KB 1,024 (210) bytes

1 MB 1,024 KB or 1,0242 bytes

1 GB 1,024 MB or 1,0243 bytes

1 TB 1,024 GB or 1,0244 bytes

1 PB 1,024 TB or 1,0245 bytes

1 EB 1,024 PB or 1,0246 bytes


Accessing product documentationProduct user documentation is available on Hitachi Data Systems SupportConnect: https://support.hds.com/en_us/documents.html. Check this site forthe most current documentation, including important updates that may havebeen made after the release of the product.

Getting helpHitachi Data Systems Support Connect is the destination for technical supportof products and solutions sold by Hitachi Data Systems. To contact technicalsupport, log on to Hitachi Data Systems Support Connect for contactinformation: https://support.hds.com/en_us/contact-us.html.

Hitachi Data Systems Community is a global online community for HDScustomers, partners, independent software vendors, employees, andprospects. It is the destination to get answers, discover insights, and makeconnections. Join the conversation today! Go to community.hds.com,register, and complete your profile.

CommentsPlease send us your comments on this document to [email protected] the document title and number, including the revision level (forexample, -07), and refer to specific sections and paragraphs wheneverpossible. All comments become the property of Hitachi Data SystemsCorporation.

Thank you!


https://support.hds.com/en_us/documents.htmlhttps://support.hds.com/en_us/contact-us.htmlhttps://support.hds.com/en_us/contact-us.htmlhttps://community.hds.com/welcomehttps://community.hds.com/welcomemailto:[email protected]

1Introduction to provisioning

Provisioning a storage system requires balancing the costs of the solutionwith the benefits that the solution provides. The following is an overview ofprovisioning strategies that you can implement on a Hitachi Virtual StoragePlatform G1000 storage system to support your business.

About provisioning

Key terms

Basic provisioning

Thin provisioning

Requirements

About cache management devices

Introduction to provisioning 19Hitachi Virtual Storage Platform G1000 Provisioning Guide for Open Systems

About provisioningProvisioning is a method of managing storage system devices or volumes.Some provisioning methods are host-based, while others use existing storagesystem capabilities such as concatenated array groups. Some provisioningmethods are hardware-based, and others are software-based. Each techniquehas its particular use and benefit, for example, capacity, reliability,performance, or cost considerations, in a given storage environment. Used inthe wrong scenario, each can be expensive, awkward, time consuming toconfigure and maintain, and can be potentially error prone. Your supportrepresentatives are available to help you configure the highest qualitysolution for your storage environment.

Provisioning strategies fall into two fundamental categories:1. Basic provisioning on page 21 (or traditional provisioning). Basic

provisioning includes logical devices (LDEVs) and custom-sized volumes.2. Dynamic Provisioning on page 25 (or virtual provisioning). Thin

provisioning includes pooling physical storage and creating logicaldevices for hosts.

Key termsThe following are provisioning key terms:

Term Description

access attributes Security function used to control the access to a logical volume. Accessattributes are assigned to each volume: read only, read/write, andprotect.

CV (variable volume) Customized Volume. A fixed volume that is divided into arbitrary sizes.

DP pool A group of DP-VOL. The DP pool consists of one or more pool-VOLs.

DP-VOL Dynamic Provisioning virtual volume.

expiration lock Security option used to allow or not allow changing of the access attributeon a volume.

FV Abbreviation for fixed-sized volume.

meta_resource A resource group in which additional resources (other than externalvolumes) and the resources existing before installing Resource PartitionManager belong.

page In Dynamic Provisioning, a page is 42 MB of continuous storage allocatedfrom a DP pool to store data written to a DP-VOL.

pool A set of volumes that are reserved for storing Dynamic Provisioning orThin Image write data.

pool threshold In Dynamic Provisioning, the proportion (%) of used capacity of the poolto the total pool capacity. Each pool has its own pool threshold values forwarning and depletion.

20 Introduction to provisioningHitachi Virtual Storage Platform G1000 Provisioning Guide for Open Systems

Term Description

pool-VOL, pool volume A volume that is reserved for storing Dynamic Provisioning data or ThinImage operations.

resource group A group that is assigned one or more resources of the storage system.The resources that can be assigned to the resource group are LDEV IDs,parity groups, iSCSI targets, external volumes, ports, and host group IDs.

subscription limit In a thin provisioned storage system, the proportion (%) of total DP-VOLcapacity associated with the pool versus the total capacity of the DP pool.

You can set the percentage of DP-VOL capacity that can be created to thetotal capacity of the pool. This can help prevent DP-VOL blocking causedby a full pool.

For example, when the subscription limit is set to 100%, the total DP-VOLcapacity is equal to the DP pool capacity.

tier boundary The value of the reached maximum I/O counts that each tier can process.

tier relocation A combination of determining the appropriate storage tier and migratingthe pages to the appropriate tier.

tiered storage A storage hierarchy of layered structures of data drives consisting ofdifferent performance levels, or tiers, that match data accessrequirements with the appropriate performance tiers.

Basic provisioningSeveral basic provisioning techniques traditionally are used to managestorage volumes. These strategies are useful in specific scenarios based onuser needs, such as what type of storage to use or how to manually sizevolumes.

Basic provisioning relies on carving up physical storage into smaller units.Custom sizing is possible, and requires using Virtual LUN software.

Basic provisioning includes: Fixed-sized provisioning on page 21 Custom-sized provisioning on page 23

Fixed-sized provisioning

Overview of fixed-sized provisioning

Two traditional fixed-size host-based volume management methods typicallyare used on open systems to organize storage space on a server. One methodis the direct use of physical volumes as devices for use either as raw space oras a local file system. These are fixed-size volumes with a fixed number ofdisks, and as such, each has a certain inherent physical random input/outputoperation per second (IOPS) or sequential throughput (megabytes persecond) capacity. A system administrator manages the aggregate serverworkloads against them. As workloads exceed the volume's available space


or its IOPS capacity, the data is manually moved onto a larger or fastervolume, if possible.

The following figure illustrates a simple fixed-size provisioning environmentusing individual fixed volumes on a host:

The other method is to use a host-based Logical Volume Manager (LVM)where the planned workloads require either more space or IOPS capacitythan the individual physical volumes can provide. LVM is the diskmanagement feature available on UNIX-based operating systems, includingLinux, that manages their logical volumes.

The following illustrates a fixed-size provisioning environment using LUNs inhost-managed logical volumes:

With either method, hosts recognize the size as fixed regardless of the actualused size. Therefore, it is not necessary to expand the volume (LDEV) size inthe future if the actual used size does not exceed the fixed size.

When such a logical volume runs out of space or IOPS capacity, you canreplace it with one that was created with even more physical volumes thencopy over all of the user data. In some cases, it is best to add a second


logical volume then manually relocate only part of the existing data toredistribute the workload across two such volumes. These two logicalvolumes would be mapped to the server using separate host paths.

Disadvantages

Some disadvantages to using fixed-sized provisioning are: If you use only part of the entire capacity specified by an emulation type,

the rest of the capacity is wasted. After creating fixed-sized volumes, typically some physical capacity will be

wasted. In a fixed-sized environment, manual intervention can become a costly

and tedious exercise when a larger volume size is required.

When to use fixed-sized provisioning

Use fixed-sized provisioning when custom-sized provisioning is notsupported.

Custom-sized provisioning

Overview of custom-sized provisioning

Custom-sized (or variable-sized) provisioning has more flexibility than fixed-sized provisioning and is the traditional storage-based volume managementstrategy.

To create custom-sized volumes on a storage system, an administratorcreates volumes of the desired size from individual array groups. Thesevolumes are then individually mapped to one or more host ports as a logicalunit.

Following are three scenarios where custom-sized provisioning is anadvantage: In fixed-sized provisioning, when several important files are located on the

same volume and one unimportant file is being accessed, users cannotaccess the important files because of logical device contention ifCompatible PAV or Compatible Hyper PAV are not being used. If thecustom-sized feature is used to divide the volume into several smallervolumes and I/O workload is balanced (each file is allocated to a differentvolume), then access contention is reduced and access performance isimproved.

In fixed-sized provisioning, all of the volume's capacity might not be used.Unused capacity on the volume will remain inaccessible to other users. Ifthe custom-sized feature is used, smaller volumes can be created that donot waste capacity.

Applications that require the capacity of many fixed-sized volumes caninstead be given fewer large volumes to relieve device addressingconstraints.


The following illustrates custom-sized provisioning in an open-systemsenvironment using standard volumes of independent array groups:

To change the size of a volume already in use, you first create a new volumelarger (if possible) than the old one, and then move the contents of the oldvolume to the new one. The new volume would be remapped on the server totake the mount point of the old one, which is retired.

A disadvantage is that this manual intervention can become costly andtedious and this provisioning strategy is appropriate only in certain scenarios.

When to use custom-sized provisioning

Use custom-sized provisioning when you want to manually control andmonitor your storage resources and usage scenarios.

Basic provisioning workflowThe following illustrates the basic provisioning workflow:


Virtual LUN software is used to configure custom-sized provisioning. Fordetailed information, see Configuring custom-sized provisioning onpage 73.

Thin provisioningThin provisioning is an approach to managing storage that maximizesphysical storage capacity. Instead of reserving a fixed amount of storage fora volume, it simply assigns capacity from the available physical pool whendata is actually written to disk.

Dynamic Provisioning

About Dynamic Provisioning

Though basic or traditional provisioning strategies can be appropriate anduseful in specific scenarios, they can be expensive to set up, awkward andtime consuming to configure, difficult to monitor, and error prone whenmaintaining storage.

Although Dynamic Provisioning requires some additional setup steps, it is asimpler alternative to the traditional provisioning methods. DynamicProvisioning allows you to reserve virtual storage capacity based onanticipated future capacity needs, using virtual volumes instead of physicaldisk capacity.


Overall storage use rates might improve because you can potentially providemore virtual capacity to applications while using fewer physical disks. It canprovide lower initial cost, greater efficiency, and storage managementfreedom for storage administrators. In this way, Dynamic Provisioningsoftware: Simplifies storage management Provides a better balance of resources and optimization of performance by

default than basic provisioning Optimizes physical disk usage Can reduce device address requirements over traditional provisioning by

providing larger volume sizes.

When to use Dynamic Provisioning

Dynamic Provisioning is a best fit in an open-systems environment in thefollowing scenarios: Where the aggregation of storage pool capacity usage across many

volumes provides the best opportunity for performance optimization. For stable environments and large consistently growing files or volumes. Where device addressing constraints are a concern.

Dynamic Provisioning advantages

Advantages Without Dynamic Provisioning With Dynamic Provisioning

Reduces initialcosts

You must purchase physical diskcapacity for expected future use. Theunused capacity adds costs for boththe storage system and softwareproducts.

You can logically allocate morecapacity than is physically installed.You can purchase less capacity,reducing initial costs and you can addcapacity later by expanding the pool.

Some file systems take up little poolspace. For more details, see Operatingsystem and file system capacity onpage 132.

Reducesmanagementcosts

You must stop the storage system toreconfigure it.

When physical capacity becomesinsufficient, you can add pool capacitywithout service interruption.

In addition, with Dynamic Tiering youcan configure pool storage consistingof multiple types of data drives,including SSD, SAS, and externalvolumes. This eliminates unnecessarycosts.

Reducesmanagementlabor andincreasesavailability ofstorage volumesfor replication

As the expected physical disk capacityis purchased, the unused capacity ofthe storage system also needs to bemanaged on the storage system andon licensed products.

Licenses for storage system productsare based on used capacity rather thanthe total defined capacity.

You can allocate volumes of up to 256TB regardless of physical disk capacity.

Dynamic Tiering allows you to usestorage efficiently by automatically


Advantages Without Dynamic Provisioning With Dynamic Provisioning

migrating data to the most suitabledata drive.

Increases theperformanceefficiency of thedata drive

Because physical disk capacity isinitially purchased and installed tomeet expected future needs, portionsof the capacity may be unused. I/Oloads may concentrate on just a subsetof the storage which might decreaseperformance.

Effectively combines I/O patterns ofmany applications and evenly spreadsthe I/O activity across availablephysical resources, preventingbottlenecks in parity groupperformance. Configuring the volumesfrom multiple parity groups improvesparity group performance. This alsoincreases storage use while reducingpower and pooling requirements (totalcost of ownership).

DP-VOL with data direct mapping attribute

By using a DP-VOL for which the data direct mapping attribute is enabled,you can create a mapping of an external volume larger than 4 TB withouthaving to change its capacity as a DP-VOL of the local storage system.

A DP-VOL with the data direct mapping attribute enabled is associated withthe following pool-VOLs: an external volume for which the data directmapping attribute is enabled and a pool-VOL with System Area. For details,see Estimating the capacity of pool-VOLs with system area in the pool withdata direct mapping enabled on page 131.

To use DP-VOLs with the data direct mapping attribute enabled, you mustenable the data direct mapping attribute for pool-VOLs, pools, and DP-VOLs.

Procedure

1. In the Add External Volumes window, add a volume of an externalstorage system to an external volume group.

2. In the Create LDEVs window, create an external volume for which thedata direct mapping attribute enabled.

3. In the Create Pools window, create a Dynamic Provisioning pool for whichthe data direct mapping attribute is enabled. Specify the followingvolumes as pool-VOLs: The external volume with the data direct mapping attribute enabled. One or more normal volumes or external volumes.

4. In the Create LDEVs window, create a DP-VOL with the data directmapping attribute enabled.


5. In the Add LUN Paths window, configure a LU path to the DP-VOL withthe data direct mapping attribute enabled.

The following table shows what kind of external volumes can be added aspool-VOLs:

Operation Data direct mapping attribute of external volumes

Disabled Enabled

Add volumes to a pool withthe data direct mappingattribute enabled

The volumes can beadded.

The volumes can be added.

Add volumes to thefollowing pools: Dynamic Provisioning

pools Dynamic Tiering pools

(including active flash)

The volumes can beadded.

The volumes cannot be added.

The following table shows what kind of operations can be performedwhen the data direct mapping attribute of a Dynamic Provisioning pool isenabled or disabled:

Operation Data direct mapping attribute of the pool Remark

Disabled Enabled

Add an LDEV forwhich the datadirect mapping

The operation can beperformed.


None


attribute is disabledto the pool

Add an externalvolume for whichthe data directmapping attributeis enabled to thepool

The operation cannotbe performed.


None

Set the depletionthreshold and thewarning threshold


The operation cannotbe performed.

None

Set subscription The operation can beperformed.


None

Protect V-VOLswhen I/O fails toBlocked Pool VOL



None

Protect V-VOLswhen I/O fails toFull Pool



None

Performingrebalancing



None

Define the usedcapacity of the pool

The sum of thereserved pagescapacity and themapped capacity

The sum of thereserved pagescapacity and themapped capacity

None

Define the licensedcapacity

The sum of the pool-VOLs

The sum of pool-VOLsfor which the datadirect mappingattribute is disabled.

However, the licensecapacity does notinclude the capacity ofpool-VOLs for which thedata direct mappingattribute is enabled.

None

Expand pool The operation can beperformed.


However, the capacityof pool-VOLs withSystem Area must bereserved in advance.For details on how toestimate the capacity ofpool-VOLs with SystemArea.

None

Shrink pool The operation can beperformed.


However, if a pool-VOLfor which the datadirect mappingattribute is enabled isassociated with a DP-VOL, you cannot shrinkthe pool.

None


Delete pool The operation can beperformed.


You can delete a poolonly if there is noDP-VOL that isassociated with thepool

Create DP-VOL You can only createDP-VOLs for which thedata direct mappingattribute is disabled.

You can only create DP-VOLs for which the datadirect mappingattribute is enabled.

None

Implement achange to DynamicTiering (includingactive flash pool)



None

The following table shows what kind of operations can be performedwhen the data direct mapping attribute of a DP-VOL is enabled ordisabled:

Operation Data direct mapping attribute of the DP-VOL

Disabled Enabled

Configure LU paths The operation can beperformed.

The operation can be performed.

Format LDEVs The operation can beperformed.


Delete LDEVs The operation can beperformed.


Expand V-VOLs The operation can beperformed.

The operation cannot be performed.

Reclaim zero pages The operation can beperformed.


Execute the V-VOL fullallocation function



Protect V-VOLs whenI/O fails to Blocked PoolVOL



Protect V-VOLs whenI/O fails to Full Pool



Apply to LDEVs of SLUattribution



Dynamic Provisioning advantage example

To illustrate the merits of a Dynamic Provisioning environment, assume youhave twelve LDEVs from 12 RAID 1 (2D+2D) array groups assigned to a DPpool. All 48 disks contribute their IOPS and throughput power to all DPvolumes assigned to that pool. Instead, if more random read IOPShorsepower is desired for a pool, then the DP pool can be created with 32LDEVs from 32 RAID 5 (3D+1P) array groups, thus providing 128 disks ofIOPS power to that pool. Up to 1024 LDEVs can be assigned to a single pool,providing a considerable amount of I/O capability to just a few DP volumes.


Dynamic Provisioning high-level workflow

The following illustrates the Dynamic Provisioning workflow.

Pools comprised of pool volumes carved from accelerated compression-enabledparity groups

Accelerated compression-enabled parity groups

Data on LDEVs carved from parity groups comprised of FMC drives iscompressed before it is stored onto the drives. The default setting ofaccelerated compression is Disabled. You will need to set this feature toEnable to take advantage of the data compression services on FMC drives.

Note: If encryption is enabled on an FMC parity group, acceleratedcompression cannot be enabled on that parity group.

When you enable accelerated compression on a parity group comprised ofFMC drives: The capacity of the parity group expands to eight times the usable physical

capacity of the parity group. You can potentially carve out LDEVs from thisexpanded capacity and use them as pool volumes to create or expand apool. When you do this, you can utilize the increased available capacitybecause the data on the FMC drives has been compressed.


LDEVs carved from the accelerated compression-enabled parity groups canonly be used as pool volumes to create or expand a pool. These LDEVscannot be assigned directly to a host and must be assigned to a singlepool as pool volumes. LDEVs from a single parity group cannot be sharedamong multiple pools.

Monitoring used pool capacity and used pool capacity reserved forwriting Monitoring used pool capacity

The used pool capacity must always be monitored. As data is written toDP-VOLs and stored in the pool, in cases where DP-VOLs are over-provisioned, the pool might become full before the DP-VOLs become full.Therefore, the used pool capacity must always be monitored to preventthis from happening. A threshold value is set for the used pool capacity. Ifthe used pool capacity exceeds the threshold value, a SIM is reported anda notification is sent to the hosts. If these SIMs are reported, you canresolve the status of threshold exceeded by expanding the pool capacity orby deleting data. For details about the threshold values, see Thresholds onpage 194.

Monitoring used pool capacity reserved for writingFor the pools consisting of pool volumes carved from acceleratedcompression-enabled parity groups, you must monitor both the used poolcapacity and the used pool capacity reserved for writing. If the used poolcapacity reserved for writing exceeds the threshold value, a SIM isreported. The used pool capacity and the pool capacity reserved for writingare not always the same, and the SIMs are independent of each other. Thefollowing conditions can occur: The used pool capacity exceeds the threshold, but the used pool

capacity reserved for writing is lower than the threshold.


The used pool capacity is lower than the threshold, but the used poolcapacity reserved for writing exceeds the threshold.

Both used capacities exceed the threshold.

If SIMs are reported, you can resolve the status of the exceeded threshold byexpanding the pool capacity or by deleting unwanted data.

If pool volumes that are carved from accelerated compression-enabled paritygroup are used to create a new pool, you must estimate the data savingspercentage beforehand.

For a pool with a pool volume that has accelerated compression enabled, theused pool capacity and the used pool capacity reserved for writing aremonitored. The following shows the threshold values for the used poolcapacity and used pool capacity reserved for writing that trigger output ofSIMs when exceeded: Warning Threshold: You can set a value from 1% to 100% in 1%

increments. The initial value is 70%. Depletion Threshold: You can set a value from 1% to 100% in 1%

increments. The initial value is 80%. Prefixed Depletion Threshold: The value is set for the used capacity of the

parity group. The value is fixed at 90%.

The following figure shows the used pool capacity and used pool capacityreserved for writing with threshold values. Hereinafter, the smaller freecapacity between the pool or drive is called the remaining free capacityreserved for writing.


Data retention strategiesAfter provisioning your system, you can assign access attributes to open-system volumes to protect the volume against read, write, and copyoperations and to prevent users from configuring LU paths and commanddevices. Use the Data Retention Utility to assign access attributes.

For more information, see Configuring access attributes on page 247.

Dynamic Tiering

Dynamic Tiering

After using Dynamic Provisioning software to virtualize LUs and pool storageinto a thin provisioning strategy, the array now has all the elements in placeto offer automatic self-optimizing storage tiers provided by Hitachi DynamicTiering (HDT). Using Dynamic Tiering, you can configure a storage systemwith multiple storage tiers using different kinds of data drives, including SSD,SAS, and external volumes. This helps improve the speed and cost ofperformance. Dynamic Tiering extends and improves the functionality andvalue of Dynamic Provisioning. Both use pools of physical storage againstwhich virtual disk capacity, or V-VOLs, is defined. Each thin provisioning poolcan be configured to operate either as a DP pool or a Dynamic Tiering pool.


Automated tiering of physical storage is the logical next step for thinprovisioned enterprise arrays. Automated tiering is the ability of the array todynamically monitor and relocate data to the optimum tier of storage. Itfocuses on data segments rather than entire volumes. The functionality isentirely within the array without any mandated host level involvement.Dynamic Tiering adds another layer to the thin provisioned environment.

Using Dynamic Tiering you can: Configure physical storage into tiers consisting of multiple kinds of data

drives, including SSD, and SAS. Although host volumes are conventionallyconfigured from a common pool, the pool is efficiently configured usingmultiple kinds of data drives. Placing data that needs high performancewhile reducing storage costs by using high cost disks such as SSDs asefficiently as possible, resulting in data that is accessed infrequently beingplaced on lower cost physical storage.

Automatically migrate small portions of host volumes to the most suitabletier according to access frequency. Frequently accessed data is migrated tohigher speed, higher cost data drives (for example, SSD). Infrequentlyaccessed data is migrated to lower cost and lower speed data drives (forexample, SAS7.2K) to use the storage efficiently.

Dynamic Tiering simplifies storage administration by automating andeliminating the complexities of efficiently using tiered storage. Itautomatically moves data on pages in Dynamic Provisioning virtual volumesto the most appropriate storage media, according to workload, to maximizeservice levels and minimize total cost of storage.

Dynamic Tiering gives you: Improved storage resource usage Improved return on costly storage tiers Reduced storage management effort More automation Nondisruptive storage management Reduced costs Improved performance

Overview of tiers

When not using Dynamic Tiering data is allocated to only one kind of datadrive (typically an expensive high-speed data drive) without regard to theworkload because the volumes are configured with only one kind of datadrive. When using Dynamic Tiering, frequently access data is automaticallyallocated to the higher-speed HDT pool volumes and the lower speed drive tothe volumes of low workload. This improves performance and reduces costs.

Dynamic Tiering places the host volume's data across multiple tiers ofstorage contained in a pool. There can be up to three tiers (high-, medium-,and low-speed layers) in a pool. Dynamic Tiering determines tier usage basedon data access levels. It allocates the page with high I/O load to the upper


tier, which contains a higher speed drive, and the page with low I/O load tothe lower tier, which contains a lower speed drive.

The following figure illustrates the basic tier concept.

When to use Dynamic Tiering

Dynamic Tiering is the best fit in an environment in which DynamicProvisioning is a good fit.

For detailed information, see Configuring thin provisioning on page 123.

Active flashThe active flash feature of Dynamic Tiering monitors page accesses over aset time frame and attempts to keep the most frequently accessed pages inTier 1.

The active flash feature monitors a page's access frequency level real timeand promotes pages that suddenly became busy from a slower media tohigh-performance flash media, in real-time.

The active flash feature can be enabled on any Dynamic Tiering pool as longas you have SSD and FMD drives in Tier 1 of the pool. No specialconfiguration beyond what is needed for active flash is required.

Prompt Promotion

A primary goal of Dynamic Tiering and active flash is to have the mostfrequently access pages in Tier 1. As the workload varies in both thefrequency of access and the type of access, reads or writes, the threshold formoving pages from one tier to another changes. Dynamic Tiering generates adynamic tier range value that is used to determine which pages need to be inTier 1 and which need to be in a lower tier.

The active flash feature compares the recent the access frequency of eachpage to the Prompt Promotion threshold to determine whether a page should


be promoted to Tier 1. The Prompt Promotion threshold is a dynamicthreshold that adjusts based upon changes in workload to make mostefficient use of the SSD and FMD drives. If the recent access frequency for apage meets or exceeds the Prompt Promotion threshold, the page isrelocated to Tier 1 without waiting for the next Dynamic Tiering relocationcycle.

Certain type of I/O benefit more from being served by flash media