So I'm trying to plan out a full workflow. Starting with a SAN for current work + 6 months complete, then moving to a drobo for 6 months + 2 years complete and then ultimately ending up on tape for final archive.
Is standard practice to have 2 identical tapes made and then store them in different locations?
It might just be me, but it pays to be paranoid. I've lived through SAN and RAID failures. Given a choice I like to keep copies of 2nd tier SAN, NAS, RAID, ZFS pool, or somewhere AND on tape. If disaster recovery is explicitly important than a 2nd tape copy off site. And yes, test those tape backups/archives with restores.