z/OS DFSMSdss Storage Administration
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Example

z/OS DFSMSdss Storage Administration
SC23-6868-01

Example In the following example, volume SRC101 and SRC102 reside on LSS 01. Volume SRC203 resides on LSS 02. LSS01 and LSS02 can be in the same or different storage control units. SRC101 is selected as the verification volume.
  • The first COPY command -- by default, in SERIAL mode -- will copy the verification volume, SRC101.
  • When the first COPY command completes, the PARALLEL command instructs DFSMSdss to switch to parallel mode. DFSMSdss will execute all subsequent commands in parallel until it reaches the SERIAL command which tells DFSMSdss to wait for all previous commands to finish before proceeding.
  • The user instructs DFSMSdss to verify the state of the FlashCopy® Consistency Group using the specified verification volume during the "thaw" operation. The CGCREATED command should always be issued to thaw the volumes whether the copy commands completed successfully or not. In other words, the control statements do not need to check condition code prior to the CGCREATED command.
//SYSIN
   COPY FULL INDYNAM(SRC101) OUTDYNAM(TGT101) ADMIN DUMPCOND FCFREEZE 
   PARALLEL
   COPY FULL INDYNAM(SRC102) OUTDYNAM(TGT102) ADMIN DUMPCOND FCFREEZE 
   COPY FULL INDYNAM(SRC203) OUTDYNAM(TGT203) ADMIN DUMPCOND FCFREEZE
   SERIAL
   CGCREATED FCCGVFY(SRC101) ACCVOL(SRC101,SRC203)
/*
Note:
  1. The freeze and thaw operations require the specified devices support the FlashCopy Consistency Group function.
  2. There is one Consistency Group timer per logical subsystem (LSS) for FlashCopy.
  3. The Consistency Group timer has a default of 120 seconds. The timer value can be set via the ESS Web User Interface.
  4. The CGCREATED operation is processed at LSS level. It thaws all the volumes currently in "frozen for consistency grouping" state in the LSS that received the command. When a "thaw" command is received by an LSS that does not have any frozen volumes in a FlashCopy Consistency Group, the command is accepted, but no actual processing takes place.
  5. Multiple FlashCopy Consistency Groups with volumes in the same LSS must not be formed at the same time.
  6. When a FlashCopy Consistency Group timer expires before the "thaw" command is received on the LSS, I/O activity will be allowed to resume on all currently frozen volumes in the LSS. As a result, the copies of the volumes are likely inconsistent.
  7. When FCCGFREEZE is specified, if the FlashCopy pair failed to be established, DFSMSdss will withdraw all FlashCopy relations previously established with FCNOCOPY FCCGFREEZE option by the same DFSMSdss invocation. DFSMSdss will also stop processing the rest of the COPY FCCGFREEZE commands issued by the same invocation (e.g., in the same job step).
  8. During a CGCREATED operation, or a FCFREEZE operation that ends in error, DFSMSdss might issue a FlashCopy withdraw request for the source and target volume. If either volume is attached at device address X'0000', the system fails the FlashCopy withdraw operation with warning message ADR815W. Processing continues.

For more information, about using the FCCGFREEZE keyword on the COPY command, refer toFCCGFREEZE.

For more information about the ACCESSVOLUME and FCCGVERIFY keywords on the CGCREATED command, refer to ACCESSVOLUME and FCCGVERIFY.

For more information about FlashCopy Consistency Groups, refer toz/OS DFSMS Advanced Copy Services.

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