IBM SG24-5360-00 manual VSE/ESA Support for the RVA, What Is IXFP/SnapShot for VSE/ESA?

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1.2 VSE/ESA Support for the RVA

The RVA has been supported by VSE/ESA since its introduction. Because the RVA presents itself as logical 3380 or 3390 direct access storage devices (DASD) attached to a logical 3990 Model 3 storage control, releases of VSE/ESA supporting this logical environment have functioned with the RVA. However, until now, VSE/ESA has not provided SnapShot, deleted data space release (DDSR) or capacity reporting natively. It has depended on VM/ESA ′s IXFP and SnapShot to provide that benefit to VSE/ESA guests.

1.2.1 What Is IXFP/SnapShot for VSE/ESA?

IXFP/SnapShot for VSE/ESA is a feature of VSE Central Functions in conjunction with VSE/ESA Version 2, Release 3.1. It provides SnapShot, DDSR, and capacity reporting support for the RVA. OS/390 and VM/ESA provide two distinct productsÐIXFP and SnapShotÐfor supporting the RVA, whereas VSE/ESA has integrated many of the functions provided by these products into a single feature that implements the support in an Attention Routine command.

1.2.2 What Is SnapShot?

SnapShot, one of the three functions in IXFP/SnapShot for VSE/ESA, enables you to produce almost instantaneous copies of non-VSAM data sets, volumes, and data within CYLINDER ranges.

Note: Although not officially supported, VSAM data sets can be indirectly copied through techniques we discuss in Appendix C, ªVSE/VSAM Considerationsº on page 59.

The speed in copying is attained by exploiting the RVA′s virtual disk architecture. Snapshot produces copies without data movement. We call making a copy with SnapShot a snap. The result of a SnapShot is also called a snap.

Conventional methods of copying data on DASD consist of making a physical copy of the data on either DASD or tape. Host processors, channels, tape, and DASD controllers are involved in these conventional copy processes. Copying may take a long time, depending on available system resources.

In the RVA′s virtual disk architecture, a functional device is represented by a certain number of pointers in the FTD. Every used track has a pointer in the FTD to its back-end data. You snap a copy of the data by copying its FTD pointers. As you can imagine, snapping is a very fast process that takes seconds rather than minutes or hours. No data movement takes place, and no additional

back-end physical space is used. Both FTD pointers, the original and the copy, point to the same physical data location (see Figure 2 on page 4). Notice too that the TNT entry now has a value of 2, which indicates that the data is in use by two logical volumes.

Chapter 1. The IBM RAMAC Virtual Array 3

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Contents International Technical Support Organization Page International Technical Support Organization First Edition January Contents Peer-to-Peer Remote Copy Itso Redbook Evaluation Contents Vi Ramac Virtual Array, Peer-to Peer Remote VSE/ESA Team That Wrote This Redbook PrefaceYour comments are important to us Comments WelcomeIBM Ramac Virtual Array What Is an IBM Ramac Virtual Array?Overview of RVA and the Virtual Disk Architecture Log Structured File− Functional track table Data Compression and CompactionWhat Is SnapShot? What Is IXFP/SnapShot for VSE/ESA?VSE/ESA Support for the RVA Deleted Data Space Release What Is IXFP?Reporting Functions What Is Peer-to-Peer Remote Copy?Ramac Virtual Array, Peer-to Peer Remote VSE/ESA RVA Simplifies Your Storage Management RVA Benefits for VSE/ESADisk Capacity Ixfp AdministrationBatch Window Improvement IXFP/SnapShot for VSE/ESA Ramac Virtual ArrayRVA Data Availability Application DevelopmentHardware Pprc SnapShotRamac Virtual Array, Peer-to Peer Remote VSE/ESA Prerequisites VSE/ESA Support for the RVA1 VSE/ESA Input/Output Configuration Program VolumesHost Connection Partial Disk Minimal Init Volume Minimal InitAssgn ExecRamac Virtual Array, Peer-to Peer Remote VSE/ESA System VSE/ESA User Time IXFP/SnapShot for VSE/ESASample Batch Job to Invoke Ixfp Report Function DTRIATTN,PARM=′ Ixfp REPORT′IXFP/SnapShot for VSE/ESA Phys DetailAR 0015 CUU DEF DefinedIxfp Snap Full VolumeVSE/VSAM Reply ′ YES′ to ProceedRange of Cylinders Non-VSAM File Expired Files Ixfp DDSR,PATEV3 Total VolumeIxfp DDSR,PATEV30000-0999,NOPROMPT Ixfp DDSR,PATEV3DSN=′ test.data.3′ , Noprompt Specified FileIxfp REPORT,80E,80F Ixfp REPORT,80E Ixfp REPORT,80FIxfp Report Device Detail Report Sample Output of Ixfp Report CommandRamac Virtual Array, Peer-to Peer Remote VSE/ESA Subsystem Summary Report Device Summary ReportRamac Virtual Array, Peer-to Peer Remote VSE/ESA Peer-to-Peer Remote Copy Peer-to-Peer Remote CopyPprc Data Flow Pprc and VSE/ESA Software RequirementsInvoking peer-to-peer remote copy Pprc Hardware RequirementsSnapShot Considerations Examples of Pprcopy CommandsPrimary Devices of a Pprc Pair Secondary Devices of a Pprc PairRecovering from a Primary Site Failure Setting Up Pprc Paths and PairsDeleting Pprc Pairs and Paths Recovering from a Secondary Site FailurePhysical Connections to the RVA Determining the Channel Connection Address Determining the Logical Control Unit Number for RVARamac Virtual Array, Peer-to Peer Remote VSE/ESA Functional Device Configuration Appendix A. RVA Functional Device ConfigurationFunctional Device Configuration Screen CD23 Snap Command Appendix B. Ixfp Command ExamplesSyntax Ramac Virtual Array, Peer-to Peer Remote VSE/ESA Noprompt Using SnapShot to Copy One Volume to AnotherDEFINED-CAPACITY AR 0015 CapacityTest Prod Overall Test Prod Using SnapShot to Copy Files with Relocation Using SnapShot to Copy a File from One Volume to AnotherIXFP20I Snap Function Completed AT Other Uses of SnapShotSyntax of Ixfp Ddsr Command Details Ddsr CommandUsing Ddsr to Delete the Contents of a Volume Using Ddsr to Delete a Single Data SetReport Using Ddsr to Delete the Free Space on an RVAAR+0015 IXFP29D Ddsr for For Deletion Report Command Reporting on the Capacity of Multiple Volumes Reporting on the Capacity of a Single VolumeReporting on the Capacity of the RVA Subsystem Device Detail Report FUNC. Capacity MBJOB WCWTEST1 IXFP/SnapShot Setup Job StreamsExec DTRIATTN,PARM=′ Ixfp REPORT′ BG 0000 1A86I Following Assignments are Released BG 0000 // JOB InitdiskIxfp DDSR,80E Ready Ixfp DDSR,80F$$DITTO BLKFACTOR=1 EOJ 50.83 47.86 AR 0015 1I40I Ready$$DITTO BLKFACTOR=1 $$DITTO EOJ 726532.208 MB 117880.209 MB 57754.953 MB Appendix C. VSE/VSAM Considerations Backing up Vsam Volumes Appendix C. VSE/VSAM Considerations Ramac Virtual Array, Peer-to Peer Remote VSE/ESA Appendix D. Iocds Example Ramac Virtual Array, Peer-to Peer Remote VSE/ESA Appendix E. Special Notices Following terms are trademarks of other companies International Technical Support Organization Publications Appendix F. Related PublicationsRedbooks on CD-ROMs Other PublicationsRamac Virtual Array, Peer-to Peer Remote VSE/ESA ∙ E-mail Orders How to Get Itso RedbooksPlease send me the following IBM Redbook Fax Order FormSee CKD IndexPprc distance Please answer the following questions Itso Redbook EvaluationSG24-5360-00
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