Expanding and Converting Control Data Sets › Expand and Convert Control Data Sets

Expand and Convert Control Data Sets

To accommodate more than 510,800 Virtual Volume Entries in the Global VCAT and BSDS, modify the internal index. Change 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. The JCL found in HLQ.CCUUJCL(EXPAND) executes this command.

To index more than 510,800 VOLSERs, activate Volume Pooling. To activate Volume Pooling, update the Parmlib Directory Section to uncomment or add the VolumePoolDefinitions=OSPOOLS attribute. The OSPOOLS parmlib member is then updated with the VOLSER ranges in use by CA Vtape. If you do not know the VOLSER ranges in use, customize and execute HLQ.CCUUJCL(GENVOLPL) to create an OSPOOLS parmlib member with the current VOLSER ranges.

The control data sets are 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

For example, you have 500,000 VOLSERs in the Global VCAT and BSDS and are adding 50,000 more. The total number of records equals 7296 + 500,000 + 50,000 or 557296. Update the primary allocation amount to 557296 for the RECORDS parameters in the VSAM LDS DEFINEs in the EXPAND member.

The total records that are divided by 12 equals the number of 3390 tracks that are 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 dynamically invokes a recovery of the Global VCAT from the BSDS.

Follow these steps:

1. Calculate the number of records that are 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. Add the CONVERT parameter to the EXPAND command.
   2. Update the Global VCAT DEFINE and the BSDS DEFINE RECORDS parameters to the calculated total number of records.
   3. Change the Global VCAT DEFINE VOLUME parameter to point to one of the DASD volumes from step 2.
   4. Change the BSDS DEFINE VOLUME parameter to point to the other volume.
4. Stop all the CA Vtape Subsystems that are sharing the Global VCAT and BSDS to be expanded and converted.
5. Execute the EXPAND JCL.
6. Start one of the CA Vtape Subsystems.
7. 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.
8. Start the remaining CA Vtape Subsystems.