Before you do anything, review how you set up your DB backups.  If
they were through DRM, you should be employing DRM regimens to expire
them, rather than interfere with Delete Volhistory.  And your DB
backup retention needs to mesh with all server recovery elements,
particularly Reusedelay.  Keep recoverability objectives in mind as
you approach housekeeping.  Review that subject area in the Admin
Guide manual to assure that all needed aspects are covered.

   Richard Sims