Backup sets on disk storage should be reclaimed by Data Lifecycle management (DLM), that is as long as it is not the last backup set and as long as no linked dependent sets exist, such as later Incremental sets or (in the case of a full backup) later differential sets. Reclaims should take place on duplicate sets as well as the original sets. If differential backup jobs are duplicated from one disk storage device to another and Simplified System Protection (SSP) was enabled in the selections for the job then the backup sets for the duplicate differential sets will not be reclaimed. This failure occurs even if the expiry date has passed and another differential backup has been run.
If another full backup and duplicate is run then the sets will be reclaimed, however customers could still experience issues with disk space depending on their rotation strategy. Running the same strategy with SSP disabled does reclaim the duplicated differential sets as long as a new set exists and the expiry date has been exceeded.
Note: a DLM reclaim is a delete/erase operation performed by a background process however when the reclaim fails, this failure to ease older backup sets is often incorrectly referred to as a failure to overwrite.
A hotfix is now available for this issue in the current version(s) of the product(s) mentioned in this article. Refer to the Hotfix link under Related Documents at the end of this article to obtain the hotfix needed to resolve the issue.
Backup Exec 2012 Rev 1798 Service Pack 2 (TECH203155)