How to Prepare and Recover CA Vtape › Restore or Recover CA Vtape Control Data Sets › Recover the Global VCAT

Recover the Global VCAT

The BSDS and the Global VCAT maintain similar information. Either data set can be recovered from the other. They should be placed on separate DASD volumes, preferably in separate DASD subsystems so that they do not end up on the same physical HDA. This ensures that a single hardware failure does not damage both data sets.

The ability to recover the BSDS and the Global VCAT is an important feature of CA Vtape. We recommend that you do regular backups of the BSDS. In the unlikely event that both the BSDS and the Global VCAT are accidentally deleted or destroyed, you can restore the BSDS from a backup tape and then use it to recover the Global VCAT.

To recover the Global VCAT from the BSDS

1. Bring down all the CA Vtape subsystems that are part of the CA Vtape complex sharing the Global VCAT to be recovered.
2. Customize the sample JCL found in HLQ.CCUUJCL(RECGLVC).
   • If the Global VCAT is not accessible, the first step of the job is required to define a new Global VCAT. If the Global VCAT is accessible, the first step of the job can be commented out and NOINIT can be added to the recovery commands in the second step to reduce runtime.

     RECOVER=GLOBAL,PREFIX=prefix,NOINIT [,DROP_INELIGIBLE] [,SCRATCH]

   • If you are using Static Cache Management and the size of the DASD buffer pool has been reduced, the DROP_INELIGIBLE parameter should be added to the recovery commands. This parameter will cause cache LDSs that cannot be located or opened during the recovery job run to not be added back into the Global VCAT.

     RECOVER=GLOBAL,PREFIX=prefix,DROP_INELIGIBLE [,NOINIT] [,SCRATCH]

     If these LDSs are not dropped, they will be added back to the Global VCAT and to the cache totals. If these LDSs will not be created or corrected, dropping them will ensure that the DASD buffer totals are not artificially inflated, which affects the parmlib cache percentage parameters and the displayed cache subtotals. Dropping them will also ensure that the LIST=CACHE and Reclaim jobs will not try to process and report on them.

     If you use Dynamic Cache Management, the DROP_INELIGIBLE command has no affect on the recovery.

     Note: For additional information about the RECOVER=GLOBAL command, see the chapter "SVTSUTIL Batch Commands."

3. Submit the customized RECGLVC job to perform the recovery of the Global VCAT from the BSDS. Carefully review the job return codes and messages for any errors and take the appropriate corrective action.
4. If you are using Static Cache Management, submit the LDSADDxx jobs residing in PREFIX.SVTJCL. This will add back into the Global VCAT any static cache LDSs that were not added back by the recover job. These jobs will get non-zero return codes as many of the static cache LDSs will not need to be added back. There is no need to modify these jobs as a duplicate add will not cause any problems.

   If you are using Dynamic Cache Management, this step is not needed.

5. Start one CA Vtape subsystem in the CA Vtape complex and execute the console command SVTn D A. The correct cache totals should be displayed on the DASD cache utilization line of the display.
6. Customize and submit the sample JCL in HLQ.CCUUJCL(GRRJCL) to build the Backstore subgroup queues. If you are at a disaster recovery site where the cache is empty, this step can be skipped.
7. Start the remaining CA Vtape subsystems in the CA Vtape complex.