DPM maintains metadata for each tape in a database, referred to as the tape catalog. You can manage the retention settings for the tape catalog to determine when the catalog is pruned, which consists of removing entries from the catalog.
DPM will automatically prune the catalog when the retention range for the protection group expires. You can direct DPM to prune the catalog for all protection groups sooner to reduce the size of the database.
To specify tape catalog retention
In DPM Administrator Console, click Protection in the navigation bar.
Select a protection group.
In the Actions pane, click Specify tape catalog retention.
Select For, and then specify the duration.
To use the default retention setting, select For the duration of retention period specified for each protection group.