IBM SG24-5360-00 manual SnapShot Considerations, Primary Devices of a Pprc Pair

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5.4 SnapShot Considerations

The RVA provides the unique ability to combine SnapShot functions with PPRC functions. There are some considerations regarding the interaction of SnapShot with volumes that are part of a PPRC pair.

You cannot use SnapShot to copy data onto any volume that is part of a PPRC pair. SnapShot requires that addresses be available on the same RVA subsystem where the source of the copy resides. If SnapShot is going to be used on an RVA subsystem that also has PPRC pairs, there must be some logical volumes on that subsystem that are not part of a PPRC pair. Therefore, all 256 logical volumes in an RVA subsystem cannot be part of a PPRC pair and also use SnapShot on that same RVA.

5.4.1 Primary Devices of a PPRC Pair

You cannot use SnapShot to copy to a target that is the primary of a PPRC pair, regardless of whether the primary is in an active or suspended state. The primary volume can be the source for a SnapShot copy. Making a copy does not require modifying the PPRC state of the primary volume.

When dynamically allocating space for a SnapShot target, SnapShot uses all volumes available to it on a space available basis. It does not check PPRC status. SnapShot should not be provided a volume list that includes volumes that are part of a PPRC pair. The SnapShot copy will fail if any part of a data set is allocated to a volume that is part of a PPRC pair.

5.4.2 Secondary Devices of a PPRC Pair

If SnapShot will be used on a secondary RVA subsystem, there must be space available on the subsystem in addition to that used by PPRC pairs. You cannot have all 256 logical volumes as part of PPRC pairs.

Remember that you cannot issue reads or writes to a secondary volume of a PPRC pair. However, by using a procedure like the following, you can make SnapShot copies of data from the secondary deviceÐand return it to active status very quickly:

1.SUSPEND the pair.

2.RECOVER the secondaryÐreturning it to simplex status.

3.Make the SnapShot copy.

4.ESTPAIR RESYNC the secondary to copy only the changes from the primary.

5.5Examples of PPRCOPY Commands

In this section we demonstrate the use of the ICKDSF PPRCOPY commands to initiate a PPRC pair.

In the examples that follow, two devices are used. At the primary site, the RVA′ s SSID is x′0057′, the serial number of the storage control is 7390007, and the CCA

is x′D48′. (The serial number actually has two partsÐthe first two digits indicate

the plant of manufacture, and the last five digits are the machine serial number.) At the secondary site, the RVA′s SSID is x′053F′, the serial number of the

storage control is 7390014, and the CCA is x′D8C′. (See 5.6, ªPhysical Connections to the RVAº on page 38 for the relationship between the logical control unit number and the CCA.)

36 RAMAC Virtual Array, Peer-to Peer Remote VSE/ESA

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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 Preface Team That Wrote This RedbookComments Welcome Your comments are important to usOverview of RVA and the Virtual Disk Architecture What Is an IBM Ramac Virtual Array?IBM Ramac Virtual Array Log Structured FileData Compression and Compaction − Functional track tableWhat Is SnapShot? What Is IXFP/SnapShot for VSE/ESA?VSE/ESA Support for the RVA What Is IXFP? Deleted Data Space ReleaseWhat Is Peer-to-Peer Remote Copy? Reporting FunctionsRamac Virtual Array, Peer-to Peer Remote VSE/ESA RVA Simplifies Your Storage Management RVA Benefits for VSE/ESADisk Capacity Ixfp AdministrationBatch Window Improvement Ramac Virtual Array IXFP/SnapShot for VSE/ESARVA Data Availability Application DevelopmentHardware SnapShot PprcRamac Virtual Array, Peer-to Peer Remote VSE/ESA VSE/ESA Support for the RVA Prerequisites1 VSE/ESA Input/Output Configuration Program VolumesHost Connection Assgn Volume Minimal InitPartial Disk Minimal Init ExecRamac Virtual Array, Peer-to Peer Remote VSE/ESA IXFP/SnapShot for VSE/ESA System VSE/ESA User TimeDTRIATTN,PARM=′ Ixfp REPORT′ Sample Batch Job to Invoke Ixfp Report FunctionIXFP/SnapShot for VSE/ESA AR 0015 CUU DEF DetailPhys DefinedFull Volume Ixfp SnapReply ′ YES′ to Proceed VSE/VSAMRange of Cylinders Non-VSAM File Expired Files Ixfp DDSR,PATEV3 Total VolumeIxfp DDSR,PATEV30000-0999,NOPROMPT Specified File Ixfp DDSR,PATEV3DSN=′ test.data.3′ , NopromptIxfp REPORT,80E,80F Ixfp REPORT,80E Ixfp REPORT,80FIxfp Report Sample Output of Ixfp Report Command Device Detail ReportRamac Virtual Array, Peer-to Peer Remote VSE/ESA Device Summary Report Subsystem Summary ReportRamac Virtual Array, Peer-to Peer Remote VSE/ESA Peer-to-Peer Remote Copy Peer-to-Peer Remote CopyPprc and VSE/ESA Software Requirements Pprc Data FlowPprc Hardware Requirements Invoking peer-to-peer remote copyPrimary Devices of a Pprc Pair Examples of Pprcopy CommandsSnapShot Considerations Secondary Devices of a Pprc PairSetting Up Pprc Paths and Pairs Recovering from a Primary Site FailureDeleting Pprc Pairs and Paths Recovering from a Secondary Site FailurePhysical Connections to the RVA Determining the Logical Control Unit Number for RVA Determining the Channel Connection AddressRamac Virtual Array, Peer-to Peer Remote VSE/ESA Appendix A. RVA Functional Device Configuration Functional Device ConfigurationFunctional Device Configuration Screen CD23 Snap Command Appendix B. Ixfp Command ExamplesSyntax Ramac Virtual Array, Peer-to Peer Remote VSE/ESA Using SnapShot to Copy One Volume to Another NopromptDEFINED-CAPACITY AR 0015 CapacityTest Prod Overall Test Prod Using SnapShot to Copy a File from One Volume to Another Using SnapShot to Copy Files with RelocationOther Uses of SnapShot IXFP20I Snap Function Completed ATDdsr Command Syntax of Ixfp Ddsr Command DetailsUsing Ddsr to Delete a Single Data Set Using Ddsr to Delete the Contents of a VolumeReport Using Ddsr to Delete the Free Space on an RVAAR+0015 IXFP29D Ddsr for For Deletion Report Command Reporting on the Capacity of the RVA Subsystem Reporting on the Capacity of a Single VolumeReporting on the Capacity of Multiple Volumes Device Detail Report FUNC. Capacity MBJOB WCWTEST1 IXFP/SnapShot Setup Job StreamsExec DTRIATTN,PARM=′ Ixfp REPORT′ Ixfp DDSR,80E BG 0000 // JOB InitdiskBG 0000 1A86I Following Assignments are Released Ready Ixfp DDSR,80F50.83 47.86 AR 0015 1I40I Ready $$DITTO BLKFACTOR=1 EOJ$$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 Redbooks on CD-ROMs Appendix F. Related PublicationsInternational Technical Support Organization Publications Other PublicationsRamac Virtual Array, Peer-to Peer Remote VSE/ESA How to Get Itso Redbooks ∙ E-mail OrdersIBM Redbook Fax Order Form Please send me the followingIndex See CKDPprc distance Itso Redbook Evaluation Please answer the following questionsSG24-5360-00
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