Archiving Datasets – Mixed Retention Periods

Let us examine an example of a site that requires four backup durations to archive their reports for 7 days, 1 month, 3 months and 1 year.

If we back up all datasets created with various durations on the same tapes, as time passes "holes" start to appear in our tapes as certain archived datasets pass their expiration dates. Some of the backup products that Control-D supports, such as DMS/OS, have a Merge option. However, merge processing is both time and resource consuming, tying up multiple tape and cartridge devices as it processes, and has to be run frequently to avoid the forming of "holes."

So the mixing of various retention periods during archiving prevents us from releasing tapes into the system, and continual merge processing incurs too much overhead.