Condense: Freeing Resources in the Catalog

Whenever you back up data, you increase the size of the Catalog resources used to protect data. A large Catalog with many expired backups consumes unnecessary storage space on the master server and is time consuming to back up.

Every backup job has a retention period that defines the number of days a backup image is kept in the Catalog. Every backup job has a tape retention period that defines the number of days a backup image is kept on a media volume and in the Catalog. This period is initially set to a default value, such as 90 days, but you can change it later.

See also. To extend the retention period of Catalog jobs, see Job Functions: Managing Catalog Expiration Cycles.

When you condense the Catalog, Catalog data for backups that have passed their retention period are removed from the Catalog, freeing space on the master server. At the same time, storage used for Block backups is freed up. For tapes, when all backups on a tape have passed their retention dates, the tape status is changed to Free and the tape become available for re-use.

Condense is the primary Catalog maintenance operation. Perform it every day. Condense provides the following important functions:

• Identifies media volumes where all jobs have passed their retention period. The condense operations marks such volumes free for reuse and frees backup storage to save space.

• Reduces the size of the Catalog.

• Removes expired snapshots of Catalogic DPX from the NetApp storage systems or Catalogic DPX Open Storage Service.

During the condense operation, Catalogic DPX checks the Catalog to identify backups that have exceeded their retention time. If the retention period specified in the backup definition has passed, Catalogic DPX evaluates the associated Catalog records and frees up those resources. The condense operation does the following:

• Sets tape media volsers to empty and moves them to their designated media pools as needed.

• Deletes on-disk data for block-level backups.

• Purges file history and other metadata from the Catalog, freeing up space.

• Cleans up metadata on Block backup clients related to change journal tracking.

The condense operation checks for resources that can be freed and coordinates the necessary actions to free them. This action only occurs during condense operations.

You can recycle expired media volumes back to an alternate pool when a Catalog Condense operation is performed. For more information, see the Alternate Tape Pools > Recycle Expired Tape section in Adding a Media Pool in the Reference Guide. Alternatively, you can drag and drop media volumes from one media pool to another compatible media pool. See Moving Media Volumes in the Reference Guide.

The condense operation reduces the size of the Catalog by eliminating unneeded information. This has important benefits:

• It reduces the disk space required to store the Catalog.

• Catalogic DPX runs more efficiently by reducing the size of the Catalog that Catalogic DPX must search for a variety of operations.

It is strongly recommended to condense the Catalog every day. Do this after the Catalog backup completes, and schedule the condense for a time when there is relatively low backup activity.

Tip. Ensure adequate free space on the master server. For very large Enterprises, the Catalog condense function can require as much as 2.5 GB of free space on the partition where Catalogic DPX is installed.