We're currently "backupping" ~300TB, and we chose delayed replication on a secondary site after evaluating several solutions. With hashbackup (http://www.hashb

We're currently "backupping" ~300TB, and we chose delayed replication on a secondary site after evaluating several solutions. With hashbackup (http://www.hashbackup.com/ http://www.hashbackup.com/ - not related in any way, just a happy user), we can squeeze roughly one year of history using a differential daily/weekly/monthly schedule. It's faster than tape, and much easier to manage. If you account for electricity though, it's not much cheaper. But as we scale our storage, we can scale the other site as well (replacing hdds with higher capacity), which has allowed us to move from ~100TB to the current size without any change. That being said, if I had a high density tape (as advertised), I would definitely choose tape. I don't think I need to explain the benefits of having multiple copies.