5.2.1 OverviewThe BART retention policy results in the categorization of each backup in one of three statuses – active, obsolete, and keep:
• Active. The backup satisfies the retention policy applicable to its server. Such backups would be considered necessary to ensure the recovery safety for the server and thus should be retained.
• Obsolete. The backup does not satisfy the retention policy applicable to its server. The backup is no longer considered necessary for the recovery safety of the server and thus can be deleted.
• Keep. The backup is to be retained regardless of the retention policy applicable to its server. The backup is considered vital to the recovery safety for the server and thus should not be deleted for an indefinite period of time.
• Redundancy Retention Policy. The redundancy retention policy relies on a specified, maximum number of most recent backups to retain for a given server. When the number of backups exceeds that maximum number, the oldest backups are considered obsolete (except for backups marked as keep). Section 220.127.116.11 describes this type of retention policy.
• Recovery Window Retention Policy. The recovery window retention policy relies on a time frame (the recovery window) for when a backup should be considered active. The boundaries defining the recovery window are the current date/time (the ending boundary of the recovery window) and the date/time going back in the past for a specified length of time (the starting boundary of the recovery window). If the date/time the backup was taken is within the recovery window (that is, the backup date/time is on or after the starting date/time of the recovery window), then the backup is considered active, otherwise it is considered obsolete (except for backups marked as keep). Section 18.104.22.168 describes this type of retention policy.Thus, for the recovery window retention policy, the recovery window time frame dynamically shifts so the end of the recovery window is always the current date/time when the MANAGE subcommand is run. As you run the MANAGE subcommand at future points in time, the starting boundary of the recovery window moves forward in time.At some future point, the date/time of when a backup was taken will be earlier than the starting boundary of the recovery window. This is when an active backup’s status will then be considered obsolete.You can see the starting boundary of the recovery window at any point in time by running the SHOW-SERVERS subcommand. The RETENTION POLICY field of the SHOW-SERVERS subcommand displays the starting boundary of the recovery window.