srdf controls for tpf

8/13/2019 SRDF Controls for TPF

1/384

Revised: February 11, 2004 11:18 amTitle.fm

(Publication Template v3.6)

EMC Corporation

Corporate Headquarters:

Hopkinton, MA 01748 -91031-508 -435 -1000

www.EMC.com

EMCCO

NFIDE

NTIALSpecial Release

EMC SRDF Controls for TPFVersion 5.2.0

PRODUCT GUIDE

P/N 300-000-086REV A


2/384


EMC SRDF Controls for TPF Product Guideii

EMCCO

NFIDE

NTIAL

Copyright 2000 - 2004EMC Corporation. All rights reserved.

Printed February, 2004

EMC believes the information in this publication is accurate as of its publication date. Theinformation is subject to change without notice.

THE INFORMATION IN THIS PUBLICATION IS PROVIDED AS IS. EMC CORPORATIONMAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WITH RESPECT TO THEINFORMATION IN THIS PUBLICATION, AND SPECIFICALLY DISCLAIMS IMPLIEDWARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Use, copying, and distribution of any EMC software described in this publication requires anapplicable software license.

Trademark Information


3/384

EMC SRDF Controls for TPF Product Guide iii

EMCCO

NFIDE

NTIAL



4/384


EMC SRDF Controls for TPF Product Guideiv

EMCCO

NFIDE

NTIAL


5/384

EMC SRDF Controls for TPF Product Guide v

EMCCO

NFIDE

NTIAL

Revised: February 11, 2004 11:18 amSRDFTPFTOC.fm(Publication Template v3.6)

Preface............................................................................................................................ xv

Chapter 1 Product Overview

Overview........................................................................................... 1-2Product Features .............................................................................. 1-3Security Feature ........................................................................ 1-3Symmetrix Level Synchronization Direction........................ 1-3Remote Symmetrix Display and Configuration Operations.... 1-3SRDF Monitor............................................................................ 1-3SRDF Group and Set Name Support ..................................... 1-4

Product Requirements..................................................................... 1-5Operating System Requirements............................................ 1-5Microcode Level........................................................................ 1-5

SRDF Overview................................................................................ 1-6SRDF Configurations ............................................................... 1-6SRDF Director Hardware ........................................................ 1-7SRDF Implementations............................................................ 1-8SRDF Operational Modes........................................................ 1-8

Chapter 2 Installation

Maintenance...................................................................................... 2-2Installation Tape............................................................................... 2-3Program Directory........................................................................... 2-4Unloading the Tape ......................................................................... 2-7TPF Source Customization ............................................................. 2-9

Installing SRDF Controls .............................................................. 2-10Functional Entries .......................................................................... 2-11

Contents


6/384

EMC SRDF Controls for TPF Product Guide

EMCCO

NFIDE

NTIAL

vi

Contents

Revised: February 11, 2004 11:18 amSRDFTPFTOC.fm

Installation Considerations .......................................................... 2-12Migrating From an Earlier Release of SRDF Controls.............. 2-13

Chapter 3 SRDF Operations

Logical Volume Types ..................................................................... 3-2I/O Operations ......................................................................... 3-3

Logical Volume States ..................................................................... 3-4SRDF Volumes States (SRDF View) ....................................... 3-5Symmetrix Volume States (Host View) ................................. 3-6Host Accessibility ..................................................................... 3-7

SRDF Logical Volume Attributes .................................................. 3-9Source (R1) Volume Attributes ............................................... 3-9

Operational Modes........................................................................ 3-11Synchronous Mode................................................................. 3-12Semi-Synchronous Mode....................................................... 3-14Adaptive Copy-Write Pending (AW) .................................. 3-16

Adaptive Copy-Disk Mode (AD)......................................... 3-19Asynchronous Mode.............................................................. 3-21Resuming SRDF/A Operation ............................................. 3-22Ensuring Data Consistency The Dependent WritePrinciple ................................................................................... 3-23Concurrent RDF...................................................................... 3-24Switched SRDF Configurations............................................ 3-31

Additional SRDF Functions ......................................................... 3-33

Target (R2) Volume Read/Write Protection........................ 3-33Monitoring SRDF Operations ...................................................... 3-34VM Gatekeeper Support............................................................... 3-35

Chapter 4 SRDF Commands

ZURDF Help..................................................................................... 4-3ZURDF ADMAx|AWMAx............................................................ 4-5

ZURDF ASYNC ............................................................................... 4-8ZURDF CONfig ACCEPT|DISCARD........................................ 4-31ZURDF CONfig ADD|REMove ................................................. 4-34ZURDF CONfig CHAnge|DELete............................................. 4-37ZURDF CONfig DISplay.............................................................. 4-41ZURDF CONfig DISplay CTLRCD............................................. 4-47ZURDF CONfig OPEn|CLOse.................................................... 4-51ZURDF CONfig REName ............................................................ 4-53

ZURDF CONfig VERify................................................................ 4-54ZURDF CRTpair ............................................................................ 4-57


7/384

viiEMC SRDF Controls for TPF Product Guide

EMCCO

NFIDE

NTIAL

Contents


ZURDF CTLRCD........................................................................... 4-63

ZURDF DEFine PARm-ONL|GFL|NOG................................. 4-65ZURDF DEFine PARm-INT|DEL .............................................. 4-67ZURDF DEFine PARm-STL......................................................... 4-68ZURDF DEFine PARm-SYN........................................................ 4-69ZURDF DELpair............................................................................ 4-70ZURDF DISplay............................................................................. 4-79ZURDF DISplay CTLRCD ........................................................... 4-97ZURDF DISplay STAtus............................................................. 4-102

ZURDF INItialize CLEar............................................................ 4-104ZURDF INValidate...................................................................... 4-105ZURDF LINk................................................................................. 4-111ZURDF MIGRATE ...................................................................... 4-114ZURDF MODe............................................................................. 4-116ZURDF RDY|NRDy................................................................... 4-118ZURDF REFresh.......................................................................... 4-123ZURDF RESET............................................................................. 4-129

ZURDF RESTART ....................................................................... 4-130ZURDF RFRresume .................................................................... 4-133ZURDF SUSpend|RESume....................................................... 4-140ZURDF SWAPAIR....................................................................... 4-147ZURDF SYNchd .......................................................................... 4-153ZURDF TARget............................................................................ 4-157ZURDF VALidate ........................................................................ 4-160ZURDF WRIteenable .................................................................. 4-167

SRDF Commands Summary...................................................... 4-172

Chapter 5 SRDF Procedures

Getting Started................................................................................. 5-2Recovering Using Operational Host ............................................ 5-3

Making the Operational Site Available ................................. 5-3When Non-Operational Site Becomes Available ................. 5-4

Testing Recovery Procedures......................................................... 5-6Procedure 1: Performing R2 Read/Write Testing................ 5-8Procedure 2: Selecting a Synchronization Method............ 5-10Procedure 3-R1: Performing R1>R2 Full VolumeResynchronization From a Host With Access to the R1Volumes ................................................................................... 5-13Procedure 3-R2: Performing R1>R2 Full VolumeResynchronization From a Host With Access to the R2

Volumes ................................................................................... 5-16Procedure 4-R1: Performing R1


8/384


EMCCO

NFIDE

NTIAL

viii

Contents


Resynchronization From a Host With Access to the R1Volumes.................................................................................... 5-19Procedure 4-R2: Performing R1R2 Changed TracksResynchronization From a Host With Access to the R1Volumes.................................................................................... 5-24Procedure 5-R2: Performing R1>R2 Changed Tracks

Resynchronization From a Host With Access to the R2Volumes.................................................................................... 5-26Procedure 6-R1: Performing R1


9/384

ixEMC SRDF Controls for TPF Product Guide

EMCCO

NFIDE

NTIAL

Contents


Hardware, Software, and Other Requirements ........................ D-5Hardware Requirements........................................................ D-5Software Requirements .......................................................... D-5

EMC SRDF Controls for TPF V5.2.0 Test Plan .......................... D-6Step 1: Plan the Test ...................................................................... D-7

Planning Checklist .................................................................. D-7Step 2: Test the Installation ........................................................ D-12

Requirements:........................................................................ D-12Preparation and Installation

(EMC CE) ............................................................................... D-13Preparation and Installation (Customer)........................... D-13Apply fixes ............................................................................. D-13

Step 3: Document the Environment .......................................... D-14Requirements......................................................................... D-14Objective................................................................................. D-14

Step 4: Test the SRDF Configuration ........................................ D-15Define the SRDF Controls Monitor Characteristics ......... D-17

Display the SRDF Control Records .................................... D-17Step 5: Test SRDF Controls Operations on an SRDF Group . D-18Step 6: Test SRDF Controls Operations by Range .................. D-20Step 7: Test SRDF Controls Operations on a Single Device .. D-21Step 8: Test Component Failure ................................................. D-22

Test Drive Failure of Source (R1) ........................................ D-22Test Drive Failure of Target (R2) ......................................... D-22Test DA Failure...................................................................... D-22

Step 11: Test Performance Impact ............................................. D-23Requirements......................................................................... D-23Objective................................................................................. D-23Runtime .................................................................................. D-23Average I/O Response Times.............................................. D-23Peak I/O Response Times.................................................... D-23Cache Hit and Disconnect Times........................................ D-24

Step 12: Complete Test Program Exit Survey .......................... D-25

Customer Testing Survey..................................................... D-25Sending to EMC .................................................................... D-25

Appendix E Customer Support

Overview of Detecting and Resolving Problems ....................... E-2Troubleshooting the Problem ....................................................... E-3Before Calling the Customer Support Center ............................ E-4

Documenting the Problem ............................................................ E-5Reporting a New Problem ............................................................ E-6

Revised: February 11 2004 11:18 am


10/384


EMCCO

NFIDE

NTIAL

x

Contents


Sending Problem Documentation ............................................... E-7

Glossary ........................................................................................................................ g-1

Index................................................................................................................................ i-1

Revised: February 11 2004 11:18 am


11/384


EMCCO

NFIDE

NTIAL

xi

Revised: February 11, 2004 11:18 amSRDFTPFLOF.fm(Publication Template v3.6)

3-1 SRDF Logical Volume State ........................................................................ 3-43-2 Synchronous Mode .................................................................................... 3-133-3 Semi-synchronous Mode ........................................................................... 3-153-4 SRDF/A Mode Overview ......................................................................... 3-223-5 Concurrent RDF Configuration ................................................................ 3-253-6 Concurrent RDF Configuration Example ............................................... 3-273-7 Multi-hop Configuration Example .......................................................... 3-293-8 Switched SRDF Configuration ................................................................. 3-315-1 R2 Read/Write Test ...................................................................................... 5-95-2 Synchronization Method ........................................................................... 5-125-3 R1>R2 Full Volume Resynchronization From a Single Host With Access to

R1 Volumes 5-15

5-4 R1>R2 Full Volume Resynchronization From a Single Host With Access toR2 Volumes 5-185-5 R1R2 Changed Tracks Resynchronization From a Single Host With Ac-cess to the R2 Volumes 5-275-9 R1


12/384

EMCC

ONFID

ENTIAL

xii EMC SRDF Controls for TPF Product Guide

Figures

y ,SRDFTPFLOF.fm

Revised: February 11, 2004 11:18 am


13/384

EMCC

ONFID

ENTIAL

ySRDFTPFLOT.fm(Publication Template v3.6)

EMC SRDF Controls for TPF Product Guide xiii

2-1 Installation Tape Contents .......................................................................... 2-33-1 Source (R1) Volume Accessibility .............................................................. 3-73-2 Target (R2) Volume Accessibility ............................................................... 3-74-1 ZURDF ASYNC Requirements .................................................................. 4-84-2 SRDF Commands Summary ................................................................... 4-1725-1 Select a Synchronization Procedure ......................................................... 5-11A-1 EMC SIM Messages ................................................................................... A-33B-1 Link Status & Recovery ............................................................................... B-2B-2 Volume Status & Recovery ........................................................................ B-3D-1 Customer Contacts ...................................................................................... D-7D-2 EMC Contacts .............................................................................................. D-8D-3 Test Activity List .......................................................................................... D-8

Tables



14/384

EMCC

ONFID

ENTIAL


Tables

SRDFTPFLOT.fm

xiv



15/384

Preface.fm(Publication Template v3.6)

EMCC

ONFID

ENTIAL

EMC SRDF Controls for TPF Product Guide xv

Preface

As part of an effort to improve and enhance the performance and capabilitiesof its product line, EMC from time to time releases revisions of its hardwareand software. Therefore, some functions described in thisguide may not be

supported by all revisions of the software or hardware currently in use. Forthe most up-to-date information on product features, refer to your productrelease notes.

If a product does not function properly or does not function as described inthis guide, please contact your EMC representative.

Audience This guide provides instructions for the operation of EMC SRDF

Controls for TPF. Readers of this guide are expected to be familiarwith the following topics:

Symmetrix operation

TPF operating system

Organization Here is an overview of where information is located in this guide.

Chapter 1, Product Overview, provides an overview of SRDF Controls

including its features and requirements.

Chapter 2, Installation, provides the information necessary for theinstallation of SRDF Controls.

Chapter 3, SRDF Operations, provides a description of Symmetrixvolume configuration and attributes, SRDF modes of operation, andintegrated operations for the SRDF Controls.

Chapter 4, SRDF Commands, provides a description of the SRDFcommands.

Revised: February 11, 2004 11:18 amP f f


16/384

Preface.fm

EMCC

ONFID

ENTIAL

xvi EMC SRDF Controls for TPF Product Guide

Preface

Chapter 5, SRDF Procedures, outlines the steps involved inperforming data recovery procedures in an SRDF environment.

Appendix A,Messages, describes and lists the messages reported bySRDF Controls for TPF, the reason for the message, and therecommended user action.

Appendix B, Recovery Procedures, describes the status of individualSRDF volumes and Remote Link Directors, including their impact onthe host, probable cause, and the actions required to return to anormal operating status.

Appendix C, SRDF Operation Return Codes, contains information onSRDF return codes.

Appendix D, Comprehensive Test Plan, provides guidelines for EMCTimeFinder for TPF evaluation and pre-implementation testing forthe customer, systems engineer, and professional services.

Appendix E, Customer Support, reviews the EMC process for detecting

and resolving software problems, and provides essential questionsthat you should answer before contacting the EMC CustomerSupport Center.

The Glossarydescribes terms used in this manual.

RelatedDocumentation

Other related publications include:

EMC ResourcePak for TPF Product Guide,

P/N 300-000-644, EMC Corporation EMC TimeFinder Controls for TPF Product Guide,

P/N 300-000-089, EMC Corporation

Symmetrix Models 3830/5830 Product Manual,P/N 300-840-002, EMC Corporation

Symmetrix Models 3930/5930 Product Manual,P/N 300-818-001, EMC Corporation

Symmetrix Model 5200 Product Manual,P/N 200-811-554, EMC Corporation

Symmetrix Model 53xx Product Manual,P/N 200-857-550, EMC Corporation

Symmetrix Model 54xx Product Manual,P/N 200-840-550, EMC Corporation


Revised: February 11, 2004 11:18 amPreface fm


17/384

EMCC

ONFID

ENTIAL

EMC SRDF Controls for TPF Product Guide xvii

Preface

Preface.fm




Symmetrix DMX800 Product Guide,P/N 300-000-664, EMC Corporation

Symmetrix DMX1000 and DMX2000 Product Guide,P/N 300-000-661, EMC Corporation

Symmetrix Remote Data Facility (SRDF) Product Guide,P/N 200-999-554, EMC Corporation

Conventions Used inthis Guide

EMC uses the following conventions.

Red change bars in the left margin indicate new material added for

SRDF/A.

A note presents information that is important, but not hazard-related.

CAUTIONA caution contains information essential to avoid data loss ordamage to the system or equipment. The caution may apply to

EMC uses the following type style conventions in this guide:

AVANT

GARDE

Keystrokes

Palatino,bold

Dialog box, button, icon, and menu items in text Selections you can make from the user interface,

including buttons, icons, options, and fieldnames

Palatino,italic

New terms or unique word usage in text Command line arguments when used in text Book titles

Courier,

italic

Arguments used in examples of command linesyntax.

Revised: February 11, 2004 11:18 amPreface fm


18/384

Preface.fm

EMCCON

FIDEN

TIAL

xviii EMC SRDF Controls for TPF Product Guide

Preface

TPF type conventionsThe syntax conventions used in this manual are:

BOLD CAPITALIZATION= must be typed to issue a command [ ] = optional entry italics= parameter | = alternative parameter value UNDERSCORED= default

Where to Get Help For questions about technical support, call your local sales office orservice provider.

If you have a valid EMC service contract, contact EMC CustomerService at:

Follow the voice menu prompts to open a service call and select theapplicable product support.

Sales and CustomerService Contacts

For the list of EMC sales locations, please access the EMC home pageat:

http://www.EMC.com/contact/For additional information on the EMC products and servicesavailable to customers and partners, refer to the EMC Powerlink Website at:

http://powerlink.EMC.com

Courier System prompts and displays and specific

filenames or complete paths. For example:working root directory [/user/emc]:

c:\Program Files\EMC\Symapi\db

Courier,bold

User entry. For example:

symmpoll -p

United States: (800) 782-4362 (SVC-4EMC)

Canada: (800) 543-4782 (543-4SVC)

Worldwide: (508) 497-7901

Revised: February 11, 2004 11:18 amPreface.fm


19/384

EMCCON

FIDENTIAL

EMC SRDF Controls for TPF Product Guide xix

Preface

Preface.fm

Your Comments Your suggestions will help us continue to improve the accuracy,organization, and overall quality of the user publications. Please send

a message to [email protected] your opinions ofthis guide.

ProductEnhancements

The following provides a comprehensive list of enhancements forSRDF Controls for TPF:

Release 5.2.0

Support added for Dynamic RDF. Enginuity 5568 and later support the configuration anduse of Dynamic RDF devices, providing more options and flexibility in user applications.Commands have been added to create dynamic RDF pairs, delete dynamic RDF pairs, andswap dynamic RDF pairs. Possible configurations are governed by Symmetrix SRDFconnectivity and RDFGroup relationship definitions. See also configuration commandenhancements.

SRDF Group Name Enhancements:

Support added to configure SRDF Sets from subsets of RDF devices in a singleRDFGroup. Previously, Sets had to included ALL RDF device pairs configured in a

specified RDFGroup.This support also provides for configuring unpaired dynamic RDF

pairs into SRDF Sets. A configuration command has been added to add/change RDF

pairs in an SRDF Set.

A configuration command has been added to rename SRDF Groups and Sets.

A configuration command has been added to verify SRDF device pairs by CU serial

number. During the Accept phase of the Configuration process, configuration

verification ensures that a SRDF device has been configured no more than once withinan SRDF Group.

Support added for SRDF control record migration. A command has been added to migrateSRDF control records from a version 5.1.0 format to a version 5.2.0 format.

Utilization of Symmetrix API for TPF version 5.2.0 for Symmetrix running Enginuityoperating environment level 5x69 and earlier.

Release 5.1.0

Support added for Concurrent SRDF. Enginuity 5567 and later support the ability for asingle primary (source R1) volume to be remotely mirrored to two secondary (target R2)volumes concurrently. Concurrent SRDF is supported in both ESCON and Fibre ChannelRDF configurations. Commands have been enhanced to identify the secondary (target R2)device in both single and multi-hop configurations.

Support added for Switched SRDF. Enginuity 5x66 and later support SRDF over FibreChannel RDF configurations. These configurations may involve switched fabrics. The RDF

Group is used to identify the relationship between the primary (source R1) and secondary(target R2) devices on both dedicated or switch paths.

Revised: February 11, 2004 11:18 amPreface.fm


20/384

f f

EMCCON

FIDENTIAL

xx EMC SRDF Controls for TPF Product Guide

Preface

User Defined Group Name support allows the definition of Group Names and Set Namesthat can be used in display and operational commands. User Defined Group Names and SetNames replaces the SRDF Group Number and SDA designation used in earlier releases ofSRDF Controls for TPF.

Release 5.0.0

Utilization of Symmetrix API for TPF version 5.0.0 at Symmetrix microcode level 5x67 andabove.

Display SRDF Device State Matrix.

Display Device items by Range.

Display Range Status.

Enhanced Help display including Display Version.

Mixed vendor tolerance.

Enhanced operation return code reporting.

Dynamic SRDF Scheduler Time Limit.

Incorportation of prior software fixes into base code.

Release 4.0.1

Support for Symmetrix microcode level 5x67.

Release 4.0.0

Initial release of product.

Revised: February 11, 2004 11:18 amChp1.fm


21/384

(Publication Template v3.6)

Product Overview

EMCCON

FIDENTIAL

1-1

1

This chapter provides an overview of SRDF Controls including itsfeatures and requirements.

Overview.............................................................................................1-2 Product Features ................................................................................1-3 Product Requirements.......................................................................1-5 SRDF Overview..................................................................................1-6

Product Overview



22/384

EMCCON

FIDENTIAL

1

1-2 EMC SRDF Controls for TPF Product Guide

Product Overview

Overview

SRDF Controls for TPFis a TPF software package which monitorsSRDF status and controls SRDF processes through the use offunctional entries entered at the TPF prime cras.

The Symmetrix Remote Data Facility (SRDF)feature maintains areal time copy of data at the logical volume level in Symmetrix 5xxx(and later) systems located in physically separate sites.



23/384

EMCCON

FIDENTIAL

1

Product Features 1-3

Product Overview

Product Features

SRDF Controls supports features that allow for the establishment ofremote control and monitoring of data mirroring.

Security Feature SRDF Controls provides for security by allowing functional entries tobe entered from prime cras only. Additionally, SRDF Controlsoperational entries may only be entered from the prime cras of the

SYMM utility owner. SRDF Controls display entries may be issuedfrom the prime cras of any CPU in a loosely coupled complex.

Symmetrix LevelSynchronizationDirection

SRDF Controls allows synchronization direction to be set at theSymmetrix level. The synchronization direction may be set separatelyfor each Symmetrix to R1>R2, R1


24/384

EMCCON

FIDENTIAL

1


Product Overview

SRDF Group and Set

Name Support

SRDF Controls enables you to define one or more SRDF groups. Each

SRDF Group can consist of one or more user defined Sets, eachidentifying a local and remote Symmetrix SRDF pair. The same localand remote Symmetrix SRDF pair may be defined as a Set in one ormore SRDF groups. A local and remote Symmetrix pair is uniquelyidentified by the SRDF Group Name and Set Name. This designenables you to issue a single command to initiate an SRDF operationto one or all of the SRDF Sets in an SRDF group.



25/384

EMCCON

FIDENTIAL

1

Product Requirements 1-5

Product Overview

Product Requirements

This section provides the minimum system requirements for SRDFControls for TPF.

Operating SystemRequirements

SRDF Controls for TPF requires a TPF version 4.1 or higher operatingsystem environment running at IBM TPF PUT level 10 or higher, dueto the use of the TPF macro CRESC.

When running TPF under VM, SRDF Controls for TPF requires thatvolumes, through which SRDF operations are to be issued, be definedas unsupported devices. For more information about running EMCsoftware products under VM, please contact your EMCrepresentative.

SRDF Controls for TPF allows the user to predetermine a gatekeeperdevice, through which all SRDF operations for RDF devices in an

SRDF Set are to be issued. This gatekeeper device can be a general fileor other online device.

Microcode Level Before attempting to install SRDF Controls for TPF, verify that theappropriate microcode revision is present on your Symmetrix units:

Use of the SRDF command set requires the install base beSymmetrix 5000 series or higher.

Use of the SRDF command set requires the SRDF feature andmicrocode revision level 5x64 or higher. Use of certain featuresrequire higher microcode levels. These are noted whereappropriate later in this manual.

Use of SRDF Controls for TPF with Symmetrix microcode level5x64 and higher supports up to 4096 logical volumes per controlunit. If you have any questions pertaining to the microcode

version in your Symmetrix unit(s) as well as the Symmetrixfeatures installed, please contact your EMC representative.


P d t O i


26/384

EMCCON

FIDENTIAL

1


Product Overview

SRDF Overview

The Symmetrix Remote Data Facility (SRDF) feature is a businesscontinuance solution that maintains a mirror image of data at thelogical volume level in Symmetrix systems located in physicallyseparate sites.

Symmetrix SRDF offers the following major features and benefits:

high data availability

high performance flexible configurations host and applications software transparency automatic recovery from a component or link failure significantly reduced recovery time after a disaster reduced disaster recovery complexity, planning, testing, etc. increased integrity of recovery procedures reduced backup and recovery costs

The SRDF feature is transparent to the host operating system andhost applications. It does not require additional host software forduplicating data on the Symmetrix units at thegeographically-separate sites. The participating Symmetrix unitsmanage all SRDF functions.

SRDF Configurations For synchronization and coordination of SRDF activity, individual

Symmetrix units have volumes defined as either primary (source orR1) or secondary (target or R2) volumes. These volumes are thendefined as members of RDFGroups. RDFGroups are used to definethe relationships between individual Symmetrix units in an SRDFconfiguration.

An SRDF configuration has at least one primary (source or R1)volume and one secondary (target or R2) volume. Enginuity 5567 and

later supports the ability for a single primary volume to have aremote relationship or be mirrored to two secondary volumesconcurrently. This feature is called Concurrent SRDF and issupported in both ESCON and Fibre Channel SRDF configurations.

SRDF configurations may transfer data in a uni-directional orbi-directional manner. In a uni-directional configuration, all primary(source or R1) volumes reside in one Symmetrix unit and allsecondary (target or R2) volumes in another Symmetrix unit. Dataflows from the primary (source R1) volumes to the secondary (target

Product Overview



27/384

EMCCON

FIDENTIAL

1

SRDF Overview 1-7

Product Overview

R2) volumes in the respective Symmetrix units under normaloperating conditions.

In a bi-directional configuration, both primary (source or R1) andsecondary (target or R2) volumes reside in each Symmetrix unit,whether source (R1) or target (R2), in the SRDF configuration. Dataflows from the primary (source R1) volumes in the respectiveSymmetrix units to the corresponding secondary (target R2) volumesin the other Symmetrix units under normal operating conditions.

SRDF DirectorHardware

SRDF director hardware provides the communications transportlayer for SRDF data and information exchanges between Symmetrixunits.

SRDF director hardware consists of two types of adapters:

ESCON Remote Adapters (RAs) Fibre Channel Remote Adapters (RAFs or RFs)

ESCON RemoteAdapters

ESCON Remote Adapters, known as RAs, are board sets that canprovide the link connections, fiber optic protocol support, andcommunications control between two Symmetrix units in an SRDFconfiguration.

The RA board set that sends data across an SRDF link is known as anRA-1. An RA-1 functions like an IBM ESCON host channel interface.

The RA board set that receives data sent across an SRDF link isknown as an RA-2. An RA-2 functions like an IBM ESCON storagedirector interface.

An ESCON SRDF link consists of an RA-1 board set in one Symmetrixunit, an RA-2 board set in another Symmetrix unit, and a fiber cableconnecting them.

An RA-1 and its corresponding RA-2 are referred to as an RA pair.Beginning with Symmetrix 4.x models, there can be multiple RApairs in an SRDF configuration.

Fibre Channel RemoteAdapter

Enginuity microcode versions 5x66 and higher support SRDF FibreChannel emulation. The Remote Adapter for Fibre (RAF or RF) is aFibre Channel board set that is Enginuity-configured as the linkbetween Symmetrix units in an SRDF configuration.


Product Overview


28/384

EMCCON

FIDENTIAL

1


Product Overview

SRDF

Implementations

SRDF offers three modes of implementation:

Campus Solution

Extended Distance Solution

SRDF FarPoint

SRDF Campus Solution The SRDF Campus Solution allows Symmetrix units to be located upto 37.5 miles (60 km) apart using fiber-optic links. Synchronous,semi-synchronous, or Adaptive Copy data copying operational

modes are available for this solution. This implementation supportsboth uni-directional and bi-directional SRDF configurations.

SRDF ExtendedDistance Solution

The SRDF Extended Distance Solution allows the Symmetrix units tobe located over 37.5 miles (60 km) apart using a T3 or E3 link.Synchronous, semi-synchronous, or Adaptive Copy data copyingmodes of operation are available for this solution. To minimize thedegradation of performance due to distance and telecommunications

delays, EMC recommends using the semi-synchronous mode. Thisimplementation mode supports only uni-directional SRDFconfigurations.

SRDF FarPoint SRDF FarPointis an optional SRDF feature that can be used withextended distance solutions (and campus solutions in a TPFenvironment) to optimize the performance of the SRDF links. Itworks by allowing each RA to transmit multiple I/Os, in series, over

each SRDF link.

For a complete description of SRDF features, functions, and configurationrefer to the EMC Symmetrix Remote Data Facility (SRDF) Product Guide.

SRDF OperationalModes

When introduced to the disaster recovery market in the mid-1990s,SRDF offered three modes of operation:

Synchronous mode acknowledges an I/O as complete when itis written to both the local and remote cache of a SymmetrixSRDF pair

Semi-synchronous mode allows the members of an SRDFvolume pair to be at most one I/O out of synchronization perlogical volume as a way to improve performance in certainenvironments

Product Overview



29/384

EMCCON

FIDENTIAL

1

SRDF Overview 1-9

Product Overview

Adaptive Copy mode a data movement solution that sendsdata to the remote side in random order

The term asynchronous was specifically excluded from the SRDFlexicon. This practice changed with the introduction of SRDF/Amode in Enginuity level 5670. A new SRDF mode was added:

Asynchronous mode a data movement solution that sends aconsistent point-in-time image to the R2 side, which is not too farbehind the R1 side, resulting in minimal data loss in the event of adisaster at the primary site.

Asynchronous mode is available with Enginuity level 5670. This level ofEnginuity only supports single local and remote Symmetrix pairs.


Product Overview


30/384

EMCCON

FIDENTIAL

1


Revised: February 11, 2004 11:18 amChp2.fm(Publication Template v3.6)

2


31/384

Installation

EMCCON

FIDENTIAL

2-1

2

This chapter provides the information necessary for the installation ofSRDF Controls.

Maintenance........................................................................................2-2 Installation Tape .................................................................................2-3 Program Directory .............................................................................2-4 Unloading the Tape............................................................................2-7 TPF Source Customization ...............................................................2-9 Installing SRDF Controls ................................................................2-10 Functional Entries ............................................................................2-11 Installation Considerations.............................................................2-12 Migrating From an Earlier Release of SRDF Controls................2-13

Installation


2Installation


32/384

EMCCON

FIDENTIAL

2


Maintenance

Maintenance updates and current release notes are available on theEMC FTP site. Instructions for locating and downloading specificfixes and documentation are provided in the ReadMetext file storedon the FTP site:

ftp.emc.com/pub/tpfsoft/xxxxxxxx

For security reasons, the low level directory name xxxxxxxxis renamedfrom time to time.

The FTP site can be accessed from MVS or with an internet browser.Do the following from a TSO session to download the ReadMe file:

1. FTPftp.emc.com.

2. Sign on.

Sign on as user ftp. Enter your email address as the password (forexample, [email protected]).

3. Enter cd pub/tpfsoft/xxxxxxxx

4. Get ReadMe your.data.set(readme).

The FTP site is case sensitive. Take care to use the correct case for all entries.

2Installation



33/384

EMCCON

FIDENTIAL

2

Installation Tape 2-3

Installation Tape

SRDF Controls is distributed on a 3480 SL tape. The tape contains thefiles listed in Table 2-1.

Table 2-1 Installation Tape Contents

File Name Description Format Blocksize

1 TPF.RDF520.FILE1.OBJ Contains real-time

programs object code

IEBCOPY 12000

2 TPF.RDF520.FILE2.SRC Contains real-timeprograms source code

IEBCOPY 12000

3 TPF.RDF520.FILE3.SAM Contains samplesource for systemcomponent updates

IEBCOPY 12000


2Installation


34/384

EMCCON

FIDENTIAL

2


Program Directory

The SRDF Controls Program Directory consists of the followingelements.

File 1

Segment Description

E1AA40 Symmetrix Communication Protocols

E1AB40 Symmetrix Communication Protocols

E1AC40 Symmetrix Communication Protocols

E1AD40 Symmetrix Communication Protocols

E1AE40 Symmetrix Communication Protocols

E1AF40 Symmetrix Communication Protocols

E1AH40 Symmetrix Communication Protocols

E1AI40 Symmetrix Communication Protocols

E1A240 EMC Software common routines

E1RA40 SRDF Configuration Control Records Summary Display

E1RB40 SRDF Configuration Display

E1RC40 SRDF Configuration Open|Close|Add|Remove

E1RD40 SRDF Help Display

E1RE40 SRDF Help Display

E1RF40 SRDF Help Display

E1RG40 SRDF Display Device State Matrix

E1RH40 SRDF Defines, Monitor Reset, Control RecordBackup|Restore|Refresh

E1RI40 SRDF Migration

E1RJ40 SRDF Remote Symmetrix Control Record Refresh

E1RK40 SRDF Messages with Substitution

E1RL40 SRDF Command Processor

2Installation



35/384

EMCCON

FIDENTIAL

2

Program Directory 2-5

E1RM40 SRDF Messages

E1RN40 SRDF Messages

E1RO40 SRDF Display Symmetrix Configuration

E1RP40 SRDF Input Message Parser

E1RQ40 SRDF Display Device Status and Adaptive Copy Information

E1RR40 SRDF Display Control Record Summary

E1RS40 SRDF Command Scheduler

E1RT40 SRDF Monitor

E1RU40 SRDF Command Processor

E1RV40 SRDF Control Record Refresh

E1RW40 SRDF Link Operation Processor

E1RX40 SRDF Link Monitor

E1RY40 SRDF Monitor

E1RZ40 SRDF Input Message Parser

E1R040 SRDF Configuration Verification

E1R140 SRDF Configuration Rename

E1R240 SRDF Configuration Accept|Discard

E1R340 SRDF Configuration Remote Symmetrix Discovery

E1R440 SRDF Configuration Change|Delete

E1R540 SRDF Help Display

E1R640 SRDF Display Device Status and Adaptive Copy Information

E1R740 SRDF Display Link Status

E1R840 SRDF CRTpair | Delpair

E1R940 SRDF Help Display

File 1

Segment Description


2Installation


36/384

EMCCON

FIDENTIAL

2


File 2

Segment Description

E1A340 EMC software common routines

File 3

Segment Description

CVAB40 Sample functional message editor table entry

EMCUEQ EMC user equates

RAMFIL Sample RAMFIL statement

RIATA Sample RIATA call

USRTPF Sample program allocation statements

2Installation



37/384

EMCCON

FIDENTIAL

Unloading the Tape 2-7

Unloading the Tape

The installation tape is standard-labeled and has a volser in thefollowing format:

TRDvrmcorresponds to:

v= version

r= revision level

r= modification numberFor example, SRDF Controls for TPF version 5.2.0 has the volserTRD520.

Customize the following sample JCL to unload the tape:

// jobcard//** INSTALL OF SRDF CONTROLS FOR TPF FILES

//COPY01 EXEC PGM=IEBCOPY,REGION=4M

//INDD1 DD DSN=EMCSRC,DISP=(,PASS),// UNIT=tape-unit,VOL=SER=TRDvrm,LABEL=(1,NL)

//OUTDD1 DD DSN=your.default.FILE1.OBJ,

// DISP=(NEW,CATLG),VOL=SER=xxxxxx,// UNIT=SYSALLDA,SPACE=(CYL,(5,1,46)),

// DCB=(RECFM=FB,LRECL=80,BLKSIZE=3200)//SYSUT3 DD UNIT=SYSDA,SPACE=(CYL,10)

//SYSUT4 DD UNIT=SYSDA,SPACE=(CYL,10)

//SYSPRINT DD SYSOUT=X//SYSIN DD *

COPY OUTDD=OUTDD1,INDD=INDD1

/*

//COPY02 EXEC PGM=IEBCOPY,REGION=4M

//INDD1 DD DSN=EMCSRC,DISP=(,PASS),

// UNIT=tape-unit,VOL=SER=TRDvrm,LABEL=(2,NL)

//OUTDD1 DD DSN=your.default.FILE2.SRC,

// DISP=(NEW,CATLG),VOL=SER=xxxxxx,// UNIT=SYSALLDA,SPACE=(CYL,(5,1,46)),

// DCB=(RECFM=FB,LRECL=80,BLKSIZE=27920)



//SYSPRINT DD SYSOUT=X

//SYSIN DD *COPY OUTDD=OUTDD1,INDD=INDD1

/*//COPY03 EXEC PGM=IEBCOPY,REGION=4M


2Installation


38/384

EMCCON

FIDENTIAL


//INDD1 DD DSN=EMCSRC,DISP=(,PASS),

// UNIT=tape-unit,VOL=SER=TRDvrm,LABEL=(3,NL)

//OUTDD1 DD DSN=your.default.FILE3.SAM,// DISP=(NEW,CATLG),VOL=SER=xxxxxx,

// UNIT=SYSALLDA,SPACE=(CYL,(5,1,46)),

// DCB=(RECFM=FB,LRECL=80,BLKSIZE=27920)


//SYSUT4 DD UNIT=SYSDA,SPACE=(CYL,10)//SYSPRINT DD SYSOUT=X

//SYSIN DD *

COPY OUTDD=OUTDD1,INDD=INDD1/*

2Installation



39/384

EMCCON

FIDENTIAL

TPF Source Customization 2-9

TPF Source Customization

The following describes TPF source customization required for SRDFControls for TPF. Sample code has been included in File 3 on the tape.

a. The result of (c/15) must be rounded up to the next whole integer.

Segment Description

CVAx Add ZURDF as a BSS ONLY functional entry

FCTB Allocate n 4K fixed file ordinals for record types #EMCRD, #EMCRM,

#EMCRB. It is recommended that the user allocate enough ordinals toaccomodate the possibility of the addition of DASD subsystems orSRDF Groups.

n = 2a *(c/15) + 2a + b + 1

where:

a = the number of user defined Sets

b = the number of user defined SRDF Groups

c = the number of logical devices per Symmetrix unit a

If c is not the same for every Symmetrix unit, use the greatest numberof logical devices configured in a Symmetrix unit.

USRTPF Add entries for E1Rx and E1Ax program segments, and run theappropriate offline jobs to generate the allocator source (TABLExx) andPAT source (IPATxx).

SPRIAT Add RIATA ID=XA387,XCP=YES


2Installation


40/384

EMCCON

FIDENTIAL


Installing SRDF Controls

Follow these steps to install SRDF Controls:

1. Unload SRDF into the appropriate source, object, listing, andsample libraries.

2. Update the appropriate general functional message table. Seesample Functional Message Editor Table Entry in CVAB40 asspecified in Program Directoryon page 2-4.

3. Assemble the general functional message table.

4. Update the Basic Subsystem Face Table to allocate the appropriatenumber of 4K fixed file #EMCRD, #EMCRM, and #EMCRBrecords. See the sample RAMFIL statements as specified inProgram Directoryon page 2-4.

5. Generate and link the modified Basic Subsystem Face Table.

6. Update the Basic Subsystem RIAT with record id x'A387'attributes. See sample RIATA calls as specified in ProgramDirectoryon page 2-4.

7. Assemble the modified Basic Subsystem RIAT.

8. Assemble the SRDF User Exits provided in File 2 on the producttape.

9. Update the Basic Subsystem allocator with program allocationinput cards for SRDF. See the sample Program Allocation InputDeck statement in USRTPF as specified in Program Directoryonpage 2-4.

10. Generate the Basic Subsystem SAL table (TABLExx) and programallocation table (IPATxx).

11. Assemble the Basic Subsystem IPATxx.

12. Check the FTP web site for the latest object code and releasenotes. For instructions, seeMaintenanceon page 2-2.

13. Update image load, general file load, and online load decks withthe generated Basic Subsystem allocator version.

14. Create aBasic Subsystem image load with the modified FCTB,RIAT, functional message table, and SRDF E-type segments.

15. Load and activate the image.

The load of SRDF Controls base is now complete.

2Installation



41/384

EMCCON

FIDENTIAL

Functional Entries 2-11

Functional Entries

The following functional entries must be entered prior to using SRDFControls:

1. Add resource SYMMfor the Basic Subsystem to the processorresource ownership table.

ZPROT ADD UT SYMM BSS

Substitute BSS with the Basic Subsystem name of the TPF complex.

2. Assign resource SYMMfor the Basic Subsystem to one processorin the TPF complex.

ZPROT ASN UT SYMM BSS

Substitute BSS with the Basic Subsystem name of the TPF complex.

3. Initialize the SRDF Controls records with record ID x'A387'.

ZIFIL EMCRD/A387/00/0/nnnnnn/NNN/NZIFIL EMCRM/A387/00/0/nnnnnn/NNN/NZIFIL EMCRB/A387/00/0/nnnnnn/NNN/N


2Installation


42/384

EMCCON

FIDENTIAL


Installation Considerations

This section explains SRDF Controls for TPF considerations:

SRDF links to remote control units must be operational prior toconfiguring SRDF Controls for TPF control records. This enablesSRDF Controls to discover local and remote Symmetrix unitsproperly.

If both TimeFinder for TPF and SRDF Controls for TPF are loadedto the same TPF complex, the products must be at the sameversion levels to ensure compatibility.

2Installation



43/384

EMCCON

FIDENTIAL

Migrating From an Earlier Release of SRDF Controls 2-13

Migrating From an Earlier Release of SRDF Controls

Do the following to migrate a TPF system from an earlier release ofSRDF Controls to version 5.2.0.

The example entries in the following procedure must be tailored for yourspecific environment.

1. Display current version 5.1.0 configuration for later comparison.

(If migrating from a version early than 5.1.0, see the appropriateproduct guide for configuration display message formats.)

For example:

2. Load the new program base.

3. Backup SRDF control records, by issuing the command:

ZURDF CTLRCD BACKUP

Issue To

ZURDF DIS GRO-ccccccccSTA-ALL

Display status of each defined group.

ZURDF DIS LOC GRO-cccccccc

SET-ssssssss

Display local device control records for all

defined sets.ZURDF DIS LOC GRO-ccccccccSET-ssssssssTYP-LIN

Display link information for all local CUs inall TPF SRDF groups.

ZURDF DIS REM GRO-ccccccccSET-ssssssss

Display remote device control records for alldefined sets.

ZURDF DIS REM GRO-ccccccccSET-ssssssssTYP-LIN

Display link information for all remote CUs inall TPF SRDF groups.

ZURDF DIS CTL-CU Display CU/Set Control Records Summary.

ZURDF DIS CTL-GR Display Group Control Records Summary.

ZURDF DIS CTL-MA Display Master Control Record Summary.


2Installation


44/384

EMCCON

FIDENTIAL


4. Do the following based on the version from which you aremigrating:

If migrating from version 5.0.0 or earlier, configure the SRDFControls records by issuing the following:

If migrating from version 5.1.0, migrate the SRDF Controlscontrol records from the version 5.1.0 format to theconfiguration control records in the version 5.2.0 format, byentering the command:

ZURDF MIGRATE

For more information, refer to ZURDF MIGRATEon page 4-114.

Issue To

ZURDF INI CLEar Initialize the control records. Only use thiscommand if SRDF Control data structureswere previously initialized. Alternatively,you can ZIFIL the SRDF Controls records.

ZURDF CON OPENGROup-cccccccc

Open SRDF group(s) for configuration.

ZURDF CON ADDGROup-ccccccccSET-cccccccc SDA-ccud

MHL1-d[.dMHL2-d.d]

Add Set(s) to the SRDF group(s)specifying the SDA designating the hostaccessible Symmetrix unit and themultihop list identifying the RA group pathto the remote Symmetrix unit.

ZURDF CON CHAGROup-cccccccc

SET-cccccccc TYP-cccSDN-hhhhOTYP-ccc

OSDN-hhhhCNT-dddd

Specifies the RDF device pair(s) that willbe included for operation within the

specified set(s).

ZURDF CON CLOSE

GROup-cccccccc

Close SRDF group(s).

ZURDF CON DIS [REMOTE]

GROup-cccccccc

SET-cccccccc

Display Configuration Device ControlRecords for local and remote Symmetrix ofall Sets in all SRDF groups.

ZURDF CON DIS CTLRCD-MA Display SRDF Master Control Record

Summary.

ZURDF CON DIS CTLRCD-GR Display SRDF Group Control Record

Summary.

ZURDF CON DIS CTLRCD-CU Display SRDF CU Control RecordSummary.

ZURDF CON ACCEPT ALL Accept the new configuration, filing itto the SRDF Controls records.

2Installation



45/384

EMCCON

FIDENTIAL

Migrating From an Earlier Release of SRDF Controls 2-15

5. Re-display the environment and ensure that it is correct.

For example:

6. Accept the migrated configuration filing it down to the SRDFControls V5.2.0 control records:

For more information, refer to ZURDF CONfig ACCEPT|DISCARDonpage 4-31.

7. Refresh MFST information in the SRDF control records:

8. Resume normal SRDF operations:

Issue To

ZURDF CON DIS GRO-ccccccccSTA-ALL

Display status of each defined group.

ZURDF CON DIS LOCGRO-ccccccccSET-ssssssss

Display local device control records for alldefined sets.

ZURDF CON DIS REMGRO-ccccccccSET-ssssssss

Display remote device control records for alldefined sets.

ZURDF CON DIS CTL-CU Display CU/Set Control Records Summary.

ZURDF CON DIS CTL-GR Display Group Control Records Summary.

ZURDF CON DIS CTL-MA Display Master Control Record Summary.

Issue

ZURDF CON ACCEPT ALL

Issue

ZURDF CTLRCD REFRESH

Issue To

ZURDF SUS GROup-cccccccc Suspend SRDF operation for groupcccccccc.


2Installation


46/384

EMCC

ONFID

ENTIAL


Revised: February 11, 2004 11:18 amChp3.fm(Publication Template v3.6)

3


47/384

SRDF Operations

EMCC

ONFID

ENTIAL

3-1

This chapter provides a description of Symmetrix volumeconfiguration and attributes, SRDF modes of operation, andintegrated operations for the SRDF Controls for TPF.

Logical Volume Types........................................................................3-2 Logical Volume States........................................................................3-4 SRDF Logical Volume Attributes .....................................................3-9 Operational Modes ..........................................................................3-11 Additional SRDF Functions............................................................3-33 Monitoring SRDF Operations ........................................................3-34 VM Gatekeeper Support .................................................................3-35

SRDF Operations


3SRDF Operations


48/384

EMCC

ONFID

ENTIAL


Logical Volume Types

Within each Symmetrix unit, three logical volume types may bedefined: local, source (R1), and target (R2).

Local Volumes Local volumes are logical volumes unique to thatSymmetrix unit. That is, they are only accessible to hosts attached tothat Symmetrix unit. These logical volumes can beunmirrored/unspared volumes, internally mirrored to other localvolumes in that unit, protected by dynamic sparing, or exist as

dynamic spares.

Source (R1) Volumes Source (R1) volumes are logical volumesthat reside on a Symmetrix unit with the data on those volumesmirrored to respective target (R2) volumes on another Symmetrixunit. Should the source (R1) volume fail, Symmetrix willtransparently access the data on its corresponding target (R2)volume. When the failing volume is replaced, the remotely mirrored

pair is re-synchronized automatically as a background operationusing the data in the target (R2) volume.

Target (R2) Volumes Target (R2) volumes are a copy of the source(R1) volume in another Symmetrix unit. A target (R2) volumetypically has a default configuration mode of read-only to any hostwith access to the Symmetrix unit in which it resides. Under normaloperation, writes to the target (R2) volume occur via the link paths.However, should the source (R1) volume fail, Symmetrix will

transparently access the data on the corresponding target (R2)volume via the link paths. New writes accumulate as invalid tracks inthe Symmetrix unit containing the source (R1) volume.

During disaster recovery or any other use of SRDF in which theSymmetrix unit containing the source (R1) volume is unavailable forread/write access, the target (R2) volume can be made available forread/write operations with a host attached to the Symmetrix unit

containing the target (R2) volume.

3SRDF Operations



49/384

EMCC

ONFID

ENTIAL

Logical Volume Types 3-3

I/O Operations The Symmetrix units in an SRDF configuration can simultaneouslyperform I/O operations with source (R1), target (R2), and localvolumes. That is, the host systems connected to Symmetrix channelinterfaces have read/write access to the local and source (R1)volumes in their respective Symmetrix units. A host system may alsoaccess target (R2) volumes on the Symmetrix unit that are in readonly mode.

SRDF Controls for TPF obtains the status of remotely mirroredvolumes and moves control between the Symmetrix units during

failover operations and concurrent operations.


3SRDF Operations


50/384

EMCC

ONFID

ENTIAL


Logical Volume States

This section describes the three device states that an SRDF logicalvolume (source (R1) or target (R2)) reflects to the host connected tothat Symmetrix unit. These device states can be:

Not Ready (NR) Write-Protected (RO) Write-Enabled (RW)

Understanding how the three device states of an SRDF logicalvolume are achieved is fundamental to grasping the concepts ofSRDF operation. Make sure you fully comprehend this sectionBEFORE attempting any SRDF operations.

These device states are determined by a combination of twosub-states:

The device SRDF sub-state (SRDF view)

The device channel interface sub-state (host view)In general, you can look at the two sub-states as two layers(Figure 3-1):

An internal layer - the SRDF state

An external layer - the device channel interface state

These two layers are configured by different sets of internal

Symmetrix parameters. The state ultimately seen by the host isdetermined by the combination of the two device states. Table 3-1andTable 3-2 on page 3-7summarize the device state seen by the host asdetermined by the individual sub-states.

Figure 3-1 SRDF Logical Volume State

3SRDF Operations


For example, only when a device is write-enabled for both the


51/384

EMCC

ONFID

ENTIAL

Logical Volume States 3-5

For example, only when a device is write enabled for both thechannel state and the RDF state will the host be able to write to the

device.The following sections describes these two sub-states and how thevarious device sub-state combinations determine the actual overalldevice state reflected to the host.

SRDF Volumes States(SRDF View)

This section lists the sub-states a source (R1) or target (R2) volumecan have for SRDF operations.

Source (R1) VolumeStates

A source (R1) volume can have the state listed below for SRDFoperations.

Read/Write (RW)

In this state, the source (R1) volume is available for read/writeoperations. This is the default source (R1) volume state.

Not Ready (NR)

If the source (R1) volume fails, the host will continue to see thatvolume as available for read/write operations as all reads and/orwrites continue uninterrupted with the target (R2) volume in thatremotely mirrored pair.

Target (R2) VolumeStates

A target (R2) volume can have one of the three states listed below forsrdf operations.

Not Ready (NR)

In this state, the target (R2) volume responds interventionrequired/unit not ready to the host for all read and writeoperations to that volume. The target (R2) volume is unable toperform any SRDF operations when in this state.

Read-Only (RO)

In this state, the target (R2) volume is available for read-onlyoperations. This is the default target (R2) volume state.

Read/Write (RW)

In this state, the target (R2) volume is available for read/writeoperations.

Read/Write (RW) use of target (R2) volumes is intended for host

read/write use in disaster recovery as well as disaster recovery testing.Target (R2) volumes should not be used for extended periods of


3SRDF Operations

read/write activity. Use local volumes, or request your EMC Customer


52/384

EMCC

ONFID

ENTIAL


y q yEngineer to schedule a reconfiguration of R1/R2 volume pairs to localvolumes, to avoid extended read/write use of target (R2) volumes.

Symmetrix VolumeStates (Host View)

This section lists the states a source (R1) or target (R2) volume canhave for host operations. This represents the channel interfacestates.

Source (R1) VolumeStates

A source (R1) volume can have one of the three states listed below.

This state is seen by the host connected to the Symmetrix unit inwhich that volume resides.

Write-Enabled (RW)

In this state, the source (R1) volume is online to the host andavailable for read/write operations. This is the default source(R1) volume state.

Write-Disabled (RO)

In this state, the source (R1) volume responds device write-protectedto the host for all write operations to that volume.

RDF Not Ready (RNR)

In this state, the source (R1) volume responds interventionrequired/unit not readyto the host for all host accesses to thatvolume.

Target (R2) VolumeStates

A target (R2) volume can have one of the three states listed below.This state is seen by the host connected to the Symmetrix unit inwhich that volume resides.

Write-Enabled (RW)

In this state, the target (R2) volume is available for read/writeoperations.

Please note that since the default SRDF sub-state is read-only (RO), theoverall default target (R2) volume device state is read-only (RO).

Write-Disabled (RO)

In this state, the target (R2) volume is not available for writeoperations to that volume from any host that can access thatvolume. This is the default target (R2) volume state.

3SRDF Operations


Not Ready (NR)


53/384

EMCC

ONFID

ENTIAL

Logical Volume States 3-7

In this state, the target (R2) volume responds intervention

required/unit not readyto the host for all host accesses to thatvolume.

Host Accessibility The tables in this section describes the accessibility state of the source(R1) and target (R2) volumes to the host connected to the Symmetrixcontaining the source (R1) volumes.

The accessibility of the host to a particular Symmetrix volume

depends on its state from BOTH the host and SRDF view. Table 3-1lists the accessibility for a source (R1) volume. Table 3-2 on page 3-7lists the accessibility for a target (R2) volume.

Table 3-1 Source (R1) Volume Accessibility

Channel Interface State SRDF View State Accessibility

Write-Enabled (RW) Read/Write (RW) Read/Write (RW)

Write-Enabled (RW) RDF Not Ready (RNR) depends on target (R2) volumeavailability

Write-Disabled (RO) Read/Write (RW) Read-Only (RO)

Write-Disabled (RO) RDF Not Ready (RNR) depends on target (R2) volumeavailability

Not Ready (NR) Read/Write (RW) unavailable

Not Ready (NR) RDF Not Ready (RNR) unavailable

Table 3-2 Target (R2) Volume Accessibility


Write-Enabled (RW) RDF Not Ready (RNR) unavailable

Write-Enabled (RW) Read Only (RO) Read Only (RO)

Write-Enabled (RW) Read/Write (RW) Read/Write (RW)

Write-Disabled (RO) RDF Not Ready (RNR) unavailable

Write-Disabled (RO) Read Only (RO) Read Only (RO)

Write-Disabled (RO) Read/Write (RW) Read Only (RO)


3SRDF Operations

Table 3-2 Target (R2) Volume Accessibility (continued)


54/384

EMCC

ONFID

ENTIAL


Not Ready (NR) RDF Not Ready (RNR) unavailable

Not Ready (NR) Read Only (RO) unavailable

Not Ready (NR) Read/Write (WR) unavailable


3SRDF Operations


SRDF Logical Volume Attributes


55/384

EMCC

ONFID

ENTIAL

SRDF Logical Volume Attributes 3-9

SRDF Logical Volume Attributes

This section describes attributes that can be assigned to each SRDFlogical volume. A source (R1) or target (R2) volume can have one ormore attributes assigned to it.

Source (R1) VolumeAttributes

This section describes attributes that can be assigned to the source(R1) volumes in a Symmetrix unit. These attributes are set at thelogical volume level.

SYNC This attribute sets the remotely mirrored pair to the synchronousstate. In this state, the Symmetrix unit informs the host with access tothat volume that an I/O sequence has successfully completed onlyafter the Symmetrix unit containing the target (R2) volumeacknowledges that it has received and checked the data.

This state ensures full synchronization between the source (R1) andtarget (R2) volumes prior to the start of an I/O sequence.

SEMI-SYNC This attribute sets the remotely mirrored pair to thesemi-synchronous state. In this state, the Symmetrix unitcontaining the source (R1) volume informs the host of successfulcompletion of the I/O operation when it receives the data. The RLDtransfers each write to the target (R2) volume as the link pathbecomes available. The Symmetrix unit containing the target (R2)volume checks and acknowledges receipt of each write. If a new writeis started for a source (R1) volume before the previous write hascompleted to the target (R2) volume, the Symmetrix unit containingthe source (R1) volume temporarily disconnects from the host untilthe previous write operation is completed and acknowledged fromthe other Symmetrix unit and then reconnects to the host andcontinues processing. This state is typically used in ExtendedDistance configurations to minimize the impact on performance. It isalso used in situations where the Symmetrix unit containing thesource (R1) volume needs high performance but can tolerate a oneI/O gap in data synchronization.

Adaptive Copy - WritePending (AW)

This attribute, when set, affects the synchronized state of the remotelymirrored pair. When this attribute is enabled, Symmetrixacknowledges all writes to the source (R1) volume as if it was a localvolume. The new data accumulates in cacheuntil it is successfullywritten to the source (R1) volume and the RLD has transferred thewrite to the target (R2) volume. This attribute also has a


3SRDF Operations

user-configurable skew (write pending) threshold, that whenexceeded causes the remotely mirrored pair to operate in the


56/384

EMCC

ONFID

ENTIAL


exceeded, causes the remotely mirrored pair to operate in thepre-determined SRDF state (synchronous or semi-synchronous)when this mode is in effect. As soon as the number of write pendingsdrops below this value, the remotely mirrored pair reverts back to theAdaptive Copy-Write Pending (AW) state. The skew value isconfigured at the volume level and may be set to a value between 1and 65,535.

Adaptive Copy - Disk(AD)

This attribute when set, affects the synchronized state of the remotelymirrored pair. When this attribute is enabled, Symmetrixacknowledges all writes to source (R1) volumes as if they were localvolumes. New data accumulates as invalid trackson the source (R1)volume for subsequent transfer to the target (R2) volume. The RLDtransfers each write to the target (R2) volume whenever a link pathbecomes available. This attribute also has a user-configurable skew(maximum number of invalid tracks threshold), that when exceeded,causes the remotely mirrored volume to operate in the

pre-determined SRDF state (synchronous or semi-synchronous)when this mode is in effect. As soon as the number of invalid tracksdrops for a volume below this value, the remotely mirrored pairreverts back to the Adaptive Copy-Disk mode.

Domino Attribute This attribute, when set along with the SYNC attribute, ensures thatthe data on the source (R1) and target (R2) volumes are fullysynchronized. When this attribute is enabled, Symmetrix will forcethe other SRDF (source (R1) or target (R2)) volume to not ready andrespond intervention required/unit not ready to the host wheneverit detects one volume in a remotely mirrored pair is unavailable or alink failure has occurred. After the problem has been corrected, thenot ready volume must be made RDF ready again to the host. If thefailed volume or link is still not available when the SRDF volume ismade ready, the volume remains not ready. The domino attributeis not enabled in a TPF environment.

Under normal operating conditions (domino attribute not enabled), aremotely mirrored volume will continue processing I/Os with itshost even when an SRDF volume or link failure occurs. New datawritten to the source (R1) or target (R2) volume while its pair isunavailable or link paths are out of service are marked for latertransfer. When a link path is reestablished or the volume becomesavailable, resynchronization begins between the source (R1) andtarget (R2) volumes. Each source (R1) volume notifies the host when

synchronization completes on that volume.

3SRDF Operations


Operational Modes


57/384

EMCC

ONFID

ENTIAL

Operational Modes 3-11

Operational Modes

All SRDF operations are managed at a logical volume level. Fiveoperational modes are possible on SRDF logical volumes:

Synchronous mode Semi-synchronous mode Adaptive Copy - Write Pending mode Adaptive Copy - Disk mode Synchronous mode

These operational modes only affect those Symmetrix volumes thatare remotely mirrored. I/O operations with local volumes occur as ifthey are in a non-SRDF environment as no updates are required tovolumes at a different physical location. There is a preferred mode ofoperation for each SRDF solution. These operational modes areselectable based on the performance, distance, and speed of recoveryrequirements.

These SRDF modes of operation are set at the source (R1) volumeduring Symmetrix configuration. All source (R1) volumes areconfigured for either the synchronous or semi-synchronous mode.These two modes are considered to bepre-determinedSRDF modes.

In addition, the source (R1) volumes (all, individual, or a range) mayalso be configured for the Adaptive Copy-Write Pending or AdaptiveCopy-Disk mode. Each Adaptive Copy volume also has a skewparameter associated with it. In the Adaptive Copy-Write Pendingmode, this skew parameter is the maximum write pending threshold.In the Adaptive Copy-Disk mode, this skew parameter is themaximum invalid tracks threshold. This skew value may be set to thesame value for all Adaptive Copy volumes or be a different value foreach Adaptive Copy volume.

The Adaptive Copy mode and its skew value may be enabled (ordisabled) for individual remotely mirrored pairs or all remotely

mirrored pairs using SRDF commands.

An IML of a Symmetrix unit retains all SRDF parameter values setduring its configuration or changed using the Symmetrix serviceprocessor commands with the exception of the Adaptive Copy mode(either mode) and the skew parameter value for that mode. Theseparameters revert to the values set during configuration upon aSymmetrix IML.


3SRDF Operations

Synchronous Mode The synchronous mode is used primarily in SRDF Campus Solutions.


58/384

EMCC

ONFID

ENTIAL


y y p y pIn this operational mode, Symmetrix maintains a real-time mirror

image of the data on remotely mirrored volumes on a volume level.Data on the source (R1) and target (R2) volumes are always fullysynchronized at the completion of an I/O sequence.

In normal operation, this mode will have an impact on writeperformance to source (R1) volumes. This performance impact is dueto overhead associated with remote data transfer, fiber latency, andacknowledgment of the synchronous operation.

The Symmetrix unit containing the source (R1) volume informs thehost that an I/O sequence has successfully completed only after theSymmetrix unit containing the target (R2) volume acknowledges thatit has received and checked the data.

That is, the Symmetrix unit containing the source (R1) volumedisconnects from the channel and informs the host of successfulcompletion of the I/O operation only after the SRDF feature

determines that the data resides in cache in both Symmetrix units. If aproblem occurs with data synchronization, the Symmetrix unitcontaining the source (R1) volume sends a Unit Check with theappropriate sense bytes to the host. This causes the host to retry theI/O operation. These actions maintain data integrity and ensure thattwo copies of the data exist real-time in both systems before the I/Ocompletes.

3SRDF Operations



59/384

EMCC

ONFID

ENTIAL


Figure 3-2 Synchronous Mode

When the Symmetrix unit containing the source (R1) volume hasvalid data in cache destined for a target (R2) volume, the RemoteLink Director (RLD) transfers data to the cache in the Symmetrix unithousing the target (R2) volume via its link path. This data transfer

occurs while the Symmetrix unit containing the source (R1) volumecontinues to process I/O commands. If the Symmetrix unitcontaining the source (R1) volume does not receive acknowledgmentof a successful transfer from the other Symmetrix unit within itstimeout period or another failure occurs that prevents the datatransfer, the Symmetrix unit containing the source (R1) volume sendsa Unit Check with the appropriate sense bytes to the host.


3SRDF Operations

Semi-Synchronous The semi-synchronous mode is used primarily in SRDF Extended


60/384

EMCC

ONFID

ENTIAL


Mode Distance Solutions. In this operational mode, the Symmetrix unitcontaining the source (R1) volume maintains a semi-synchronousmirror image of its data in the Symmetrix unit containing the target(R2) volume on a volume level. Data on remotely mirrored volumesare always synchronized between the source (R1) and the target (R2)prior to initiating the next write operation to these volumes.

This mode of operation is designed for situations where highperformance is needed at the Symmetrix unit containing the source

(R1) volume and can tolerate a gap of up to one I/O (worst case) indata synchronization.

The Symmetrix unit containing the source (R1) volume informs thehost of successful completion after each write operation. When theSymmetrix unit containing the source (R1) volume has valid data incache destined for a target (R2) volume, the RLD transfers data to thecache in the Symmetrix unit containing the target (R2) volume via anavailable link path. This data transfer occurs while the Symmetrixunit containing the source (R1) volume continues to performadditional commands. If the host issues a new write operation for asource (R1) volume with a write pending status, the Symmetrix unitcontaining the source (R1) volume disconnects from the host channel.The Symmetrix unit containing the source (R1) volume then startsanother I/O operation on another channel. When the write pendingstatus is cleared (write completed and acknowledged and checked

from the target (R2) volume), the Symmetrix unit containing thesource (R1) volume reconnects to the channel and continuesprocessing the write operation on the channel from which itdisconnected. This operational mode keeps the data in the Symmetrixunit containing the target (R2) volume at most one I/O behind thedata in the Symmetrix unit containing the source (R1) volume whileminimizing the impact on local application performance. Figure 3-3illustrates this sequence of operations.

Although write operations can be held up due to synchronization betweensource (R1) and target (R2) volumes, read operations continue uninterrupted.

3SRDF Operations



61/384

EMCCO

NFIDE

NTIAL


Figure 3-3 Semi-synchronous Mode

If the Symmetrix unit containing the source (R1) volume does not getacknowledgment of a successful transfer from the Symmetrix unitcontaining the target (R2) volume within its timeout period oranother failure occurs that prevents the data transfer, the Symmetrixunit containing the source (R1) volume marks that data as non-validfor the target (R2) volume. Symmetrix will copy that data to the target(R2) volume as a background operation to reestablishsynchronization of the remotely mirrored pair.


3SRDF Operations

AdaptiveCopy Write Pending

EMC offers an additional level of SRDF operation, the AdaptiveCopy Write Pending mode The Adaptive Copy Write Pending


62/384

EMCCO

NFIDE

NTIAL


Copy-Write Pending

(AW)

Copy-Write Pending mode. The Adaptive Copy-Write Pending

mode transfers data from the source (R1) volume to the target (R2)volume and does not wait for receipt acknowledgment orsynchronization to occur. This mode is ideal for situations when alarge amount of data must be transferred to remote devices andperformance must not be compromised at the local site; or, forsituations where it is not necessary for remotely mirrored volumes tobe synchronized at all times. This operational mode keeps the data inthe Symmetrix unit containing the target (R2) volume as current tothe data in the Symmetrix unit containing the source (R1) volume aspossible.

This mode is designed to have little or no impact on performancebetween the host and the Symmetrix unit containing the source (R1)volume and offers protection against loss of data in the unlikely eventthat a source (R1) or target (R2) volume fails or all link paths are lost.

In this mode, the Symmetrix unit containing the source (R1) volumeinforms the host of successful completion after each write. When theSymmetrix unit containing the source (R1) volume has valid data incache for a remotely mirrored pair, it destages that data to the source(R1) volume and the RLD transfers data to the cache in theSymmetrix unit containing the target (R2) volume via its link path.This data transfer occurs while the Symmetrix unit containing thesource (R1) volume continues to process I/O commands. All writesfor remotely mirrored pairs accumulate in the cache of the Symmetrixunit containing the source (R1) volume as write pendings until thedata can be successfully written to both volumes.

Should a problem arise with data transfer to the Symmetrix unitcontaining the target (R2) volume or the Symmetrix unit is unable towrite the data to the source (R1) volume, the Symmetrix unitcontaining the source (R1) volume retains that data in its cache untilthe problem can be corrected and the data is successfully written to

both the source (R1) and target (R2) volumes.

The Adaptive Copy-Write Pending mode has a user-configurableskew parameter (maximum allowable write pendings) for eachsource (R1) volume configured for this mode. This parameter value,when exceeded, causes Symmetrix to switch to the pre-determinedSRDF mode (synchronous or semi-synchronous) for that remotelymirrored pair. When the number of write pending operations for a

target (R2) volume drops below the skew value, Symmetrix

3SRDF Operations


switches back to the Adaptive Copy-Write Pending mode for thatremotely mirrored pair. The skew value may range from 1 to 65,535.Th d f lt l f thi m t f h m t l mi d i


63/384

EMCCO

NFIDE

NTIAL


The default value for this parameter for each remotely mirrored pairis 65,535 (maximum value).

This mode can be enabled/disabled for one remotely mirrored pair,all remotely mirrored pairs, or a range of remotely mirrored pairsduring Symmetrix configuration or using SRDF commands. Whenthis mode is disabled, the remotely mirrored pairs operate in thepre-determined SRDF state (synchronous or semi-synchronous,whatever was configured for that pair).

Examples The Adaptive Copy-Write Pending mode is designed to:

Transfer large amounts of data with minimal impact onperformance

Allow remotely mirrored volumes to drift out of synchronizationf

srdf controls for tpf

Documents