RESTORE/RECOVER › Volume Defragmentation

Volume Defragmentation

A common, though infrequent, task at many locations is to defrag a volume, which at minimum usually means to consolidate the used tracks on the pack, such that free space is in just one or two extents. To CA Disk, it means the following:

1. Consolidate used tracks to obtain large contiguous free space extents.
2. Combine multiple extent data sets into a single extent.
3. Compress PDS data sets.
4. Relocate and reorganize ISAM data sets.
5. Reorganize VSAM clusters.
6. Compress the VTOC.

A recommended approach to doing this with CA Disk is as follows:

1. Locate and format a new mini FDS.
2. Use it in a DSCL run that archives and scratches all data sets on the pack. Follow this with a RECOVER execution to restore all of the data sets on the volume.

The advantage of using a separate FILES for this special function is that it keeps these reorganization index entries separate from the Archive/Backup entries, and speeds the time needed to process the FILES, since it contains fewer entries.

When completed, ARCHVOLS used in the temporary FILES can be deleted from your tape management system by using the following IXMAINT command:

PURGE DSN=/,VOL=/

For more information, see the user exit description of TMSCTLEX —Tape Management System Control Interface Exit in the Systems Guide.