How does VERDELETED work with Data Protection Exchange 'incremental' backups ?
Data Protection Exchange incremental backups (which back up the Exchange logs), creates uniquely named objects when stored in the Tivoli Storage Manager server. This means that there is only ever 1 version of the Log backup object. Thus, there can be a negative effect if the VERDELETED parameter of the management class to which they are bound is set to 0 (zero).
Data Protection for Exchange inactivates the 'Incremental" backups during the backup processing of the next FULL backup. The inactivation of the incremental looks to the Tivoli Storage Manager server as if the object was deleted from the client machine (there is no ACTIVE version of the object). Thus, if verdeleted is set to a value of 0, the incrementals that depend on the INACTIVATED FULL backup will be deleted immediately on the next Tivoli Storage Manager Server expiration. Note that the FULL backups are not uniquely named and would have normal version processing.
It is recommended to set verdeleted to a value of at least 1 to avoid this side-effect and use the RETONLY setting to control the length of time to manage these unique inactivated incremental objects. The RETONLY setting for the Incremental log objects should be set to the same value as the RETEXTRA that is set for the FULL backups.
- If the RETONLY setting for the Incremental is less than the FULL (RETEXTRA), this could allow the logs to be prematurely expired from the Tivoli Storage Manager server. This would then result in a restore such that the FULL cannot be rolled forward to a point in time after the FULL was taken.
- If the RETONLY is longer than the FULL (RETEXTRA), the incremental backups will be retained on the Tivoli Storage Manager server, even though they cannot be restored, because the FULL they rely on is already expired.