DRM has its own, strict discipline for managing DBbackup tapes. Once
fully implemented, according to product documentation, you should not
interfere with it via Delete Volhistory or other non-DRM commands.
The List archives contain past postings where partial implementations
and meddling have resulted in problems. Your disaster recovery
mechanisms should be allowed to proceed according to their
discipline, and not be fooled around with.

   Richard Sims     http://people.bu.edu/rbs