If there is no space available on the media, the purge option deletes archive sets that have exceeded their retention settings to create space for new sets. The recommended setting for retention is the interval between full backups. Sets that are still within their retention period are not purged, and nothing is purged if enough space is available for the new archive set. Jobs for which purge is selected fail if there is inadequate space and nothing can be purged or if purging cannot create enough space on the media. Once archives have been purged from the media, they can no longer be retrieved.
Note: Purge is not supported for tape archiving.
For more details about how purge works with retention settings, see the following topics:
Purging an archive set that has exceeded its retention period
The figure below illustrates how the purge option works. The archive media has a capacity of 110 GB, all of which is occupied by Archive Sets 1 and 2. The purge option has been selected for the current archive job. This job will write Set 3 to the media. Because no space is available on the media and Set 1 has exceeded its retention period, Set 1 is purged to make room for Set 3.
Failed attempt to purge archive sets with current retention
The figure below illustrates a failed attempt to purge archive sets with current retention. The archive media has a capacity of 110 GB, all of which is occupied by Archive Sets 1 and 2. The purge option has been selected for the current archive job, which will attempt to write Set 3 to the media. No space is available, but neither of the sets can be purged because both have current retention. The archive job fails with no impact to existing sets on the media.
Impact of a backup group on archive retention settings
The archived backup with the latest retention date determines the retention date for all sets containing backups belonging to the group. For example, if a set containing a full backup has a later retention date than the sets containing the differentials in the group, the retention setting for the set containing the full backup is applied to the sets containing the differentials. Archive sets containing the differentials cannot be purged until the retention period for the set containing the full backup has expired. For information on backup groups, see Backup groups.
The figure below illustrates the impact of a backup group on retention settings. Sets 2 and 3 have exceeded their retention. However, these sets cannot be purged. They contain backups belonging to the group associated with the full backup in Set 1. This set has not exceeded its retention. The archive job fails with no impact on the sets currently stored on the archive media.
