Catalog Maintenance Utility (FDRABRCM)

FDRABRCM is an ABR utility program that performs maintenance on the ABR catalog and the ABR scratch catalog.

The ABR catalog is a catalog that is used to store the location of ABR backup data sets. It is always used for ABR full and incremental backups, and is sometimes used for ARCHIVE backups.

The ABR scratch catalog is a catalog used to store information on the ABR backups of DASD data sets that have been scratched (data sets that are still on DASD have their backup information in the DSCBs of the data sets themselves). Entries are built in the scratch catalog only if you have the ABR DADSM exit installed, which intercepts SCRATCH and RENAME requests.

In most installations, both catalogs are stored in the same catalog, but they may also be separate. These are normal catalogs containing only non-VSAM catalog entries, although ABR uses some catalog fields for special purposes. You may manually delete entries with IDCAMS “DELETE NOSCRATCH” or IEHPROGM “UNCATLG” statements, but FDRABRCM helps automate this deletion.

FDRABRCM can:

  • Uncatalog entries from ABR scratch catalog that have expired.
  • Uncatalog entries from ABR scratch catalog that are within a specified date range.
  • Uncatalog obsolete backup data set entries from the ABR catalog.
  • Uncatalog backup data sets from the ABR catalog for volumes that no longer exist.
  • Simulate all of the functions mentioned above.

FDRABRCM statements

FDRABRCM has only one statement, PURGE, with two variations:

PURGE SCRATCH

Purges entries from the ABR scratch catalog.

PURGE BACKUP

Purges backup entries from the ABR catalog.

When to run

Under normal circumstances, the ABR catalog is self-maintaining. Entries for obsolete backup generations are automatically deleted by ABR as new generations are created; depending on your tape management system options and the retention type you use for ABR backups, your tape management system may also delete expired entries for tape backups. However, there are circumstances where obsolete backups might remain cataloged. A periodic execution of PURGE BACKUP with no other operands ensures that these entries are cleaned up.

In addition, when a DASD volume is no longer being backed up by ABR (such as a volume that no longer exists), a special PURGE BACKUP may be required to delete the backups when they are no longer required. Again, your tape management system may delete the entries when the backups expire.

The ABR scratch catalog is not self-maintaining. Entries in the scratch catalog point to backups in the ABR catalog; the scratch entries are obsolete when all of the backups they point to are deleted from the ABR catalog, but they do not go away by themselves. If you use the scratch catalog, you must periodically run PURGE SCRATCH with no other operands to identify and delete the obsolete entries.

Operands on each statement may be used to limit the operation to a subset of the catalog entries, or to specify other criteria for deletion of the entries.

 

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