Recovery Window Goal

The recovery_window_goal parameter of DBMS_RA.CREATE_PROTECTION_POLICY specifies the interval (typically in days) within which point-in-time recovery must be possible, counting backward from the current time. Consider a recovery_window_goal setting of 1 day. At midnight on August 7, the goal is recoverability to any time between the current time and midnight on August 6. At midnight on August 8, the goal is recoverability to any time between the current time and midnight on August 7, and so on.

Recovery Appliance attempts to retain sufficient backups to meet the recovery window goal defined for each database. For example, a Recovery Appliance protects databases STORE01, STORE02, and STORE03. The recovery window goal for STORE01 is 1 day. If at midnight on August 7, STORE01 needs 624.2 GB for backups to meet its recovery window goal, then the Recovery Appliance attempts to ensure that at least this much space is allocated for STORE01 backups.

If sufficient space exists in storage, then backups created before a recovery window goal may be available—although they are not guaranteed. If purging previous backups is not necessary, then the Recovery Appliance keeps them, effectively extending the time to which point-in-time recovery is available. For example, on August 7 the space available to STORE01 might be 700 GB or more, even though only 624.2 GB is required. A similar situation may exist for STORE02 and STORE03.

If sufficient space does not exist in storage, then by default (guaranteed_copy=NO) the Recovery Appliance may purge backups. When reclaiming space, the Recovery Appliance attempts to respect the recovery window requirement first.