Conversion Procedures › Expanding and Converting the Control Data Sets

Expanding and Converting the Control Data Sets

To accommodate more than 510,800 Virtual Volume Entries in the Global VCAT and BSDS, the internal index needs to be modified. The modification involves changing the index from pointing to individual records, to pointing to VSAM Control Intervals which contain sets of records.

The change in indexing occurs when the Global VCAT and BSDS are increased in size and the CONVERT parameter is coded on the EXPAND CDS,VOLUMES= command. This command is executed by the JCL found in HLQ.CCUUJCL(EXPAND).

To index more than 510,800 VOLSERs, Volume Pooling must be active. Volume Pooling is activated by updating the Parmlib Directory Section to uncomment or add the VolumePoolDefinitions=VTPOOLS attribute. The VTPOOLS parmlib member is then updated with the VOLSER ranges currently in use by CA Vtape. If you do not know the VOLSER ranges in use you can customize and execute HLQ.CCUUJCL(GENVOLPL) to create a VTPOOLS parmlib member with the current VOLSER ranges.

The control data sets are currently sized for the specific number of VOLSERs they currently index. To determine how large to allocate the new data sets, use the following formula:

7296 + current VOLSERs + additional VOLSERs = total records

If you currently have 500,000 VOLSERs in the Global VCAT and BSDS and are adding 50,000 more, the total number of records would be 7296 + 500,000 + 50,000 or 557296. The RECORDS parameters in the VSAM LDS DEFINEs in the EXPAND member would need to have their primary allocation amount updated to 557296.

The total records divided by 12 equals the number of 3390 tracks that will be required to hold one of the control data sets. Following the example above, 557296 records would require 557296 / 12 or 46,441 tracks or 3096 cylinders of DASD for each control data set.

To perform the conversion the EXPAND job will dynamically invoke a recovery of the Global VCAT from the BSDS.

To expand and convert the control data sets, follow these steps:

1. Calculate the number of records required for the new control data sets.
2. Find two DASD volumes with enough free space to allocate the new data sets.
3. Customize HLQ.CCUUJCL(EXPAND) by following the comments in the member:
   1. The CONVERT parameter should be added to the EXPAND command.
   2. The Global VCAT DEFINE and the BSDS DEFINE RECORDS parameters should be updated to the calculated total number of records.
   3. Change the Global VCAT DEFINE VOLUME parameter to point to one of the DASD volumes from step2 and the BSDS DEFINE VOLUME parameter to point to the other.
4. Release the Externalization Subgroup Queues to Backstore all Virtual Volumes. This step is only required if you normally Backstore your Virtual Volumes.
5. Stop all the CA Vtape Subsystems that are sharing the Global VCAT and BSDS to be expanded and converted.
6. Execute the EXPAND JCL.
7. Start one if the CA Vtape Subsystem.
8. If you are running with CacheManagement=Static, execute the LDSADDnn jobs you execute for disaster recovery to add the static cache LDSs to CA Vtape.
9. Execute HLQ.CCUUJCL(GRRJCL) to rebuild the Externalization Subgroup Queues. This step is only required if you normally Backstore your Virtual Volumes and did not Externalize all Virtual Volumes prior to stopping the CA Vtape Subsystems.
10. Perform any desired testing:
    1. Browse your Virtual VOLSER ranges with the CA Vtape ISPF Interface (SVTSMON CLIST).
    2. Read an existing Virtual Volume.
    3. Write to a scratch Virtual Volume.
11. Start the remaining CA Vtape Subsystems.