A VVDS automatically reclaims space used by deleted records. It grows into secondary extents only when there is no space for a new record. Even if the VVDS grows into a few secondary extents, the performance and reliability of the VVDS are not affected.

If you still need to change the size of a VVDS, you must backup all data sets that have an entry in the VVDS, remove these data sets from the volume, delete the VVDS, redefine the VVDS, and finally restore the data sets from their backups to the volume.

The following steps are suggested for this process:

1. Obtain exclusive use of the volume by: stopping work, varying the volume offline to sharing systems, or quiescing sharing systems.
2. Remove all data sets from the volume that have an entry in the VVDS. All catalog, SMS-managed data sets, and their catalogs should be removed using DFSMSdss (logical dump) or access method services (EXPORT, or REPRO followed by DELETE).

   With volumes that are not SMS-managed, you can use DFSMSdss to dump all catalog data sets from the volume with one command. With SMS-managed volumes, use DFSMSdss to dump the entire volume.

3. Delete the VVDS specifying RECOVERY.
4. Define a new VVDS specifying the desired size. The default recommended size is trk(10,10).
5. Restore the data originally on the volume, using DFSMSdss or access method services (use the same utility used to dump the data sets).

You can use DIAGNOSE to determine any differences between the rebuilt VVDS and each BCS that had data sets on the volume. Because all existing data should have been recovered to the volume, there should be no differences.