I am trying to grasp this VTL concept better.
I keep thinking in terms of how we use BRMS with our physical library (and
Iron Mountain). We don't keep any tapes with data written on them onsite
for 24 hours. Once the save is done we remove the tape the next morning
and ship it off to Iron Mountain. When BRMS asks for tapes we get them
back from Iron Mountain. BRMS keeps track of expiration, etc.
However, is a VTL more like how we use TSM (Tivoli Storage Manager)? It
backs up our PC's and PC type servers to disk. Some are copied over to
'near line' from disk to local tape which stays in the tape library. Daily
we remove a few tapes and send to Iron Mountain and we retrieve some back
from Iron Mountain. However a bulk of the restores we've done have come
from just using either disk or near line. I don't think we've ever used
the offline. TSM does all the hierarchical storage management.
I think the offline is just to have enough to rebuild TSM in case of fire.
Our BP totally manages TSM. Sure, our help desk knows how to restore
someone's spreadsheet or whatever from it. And our operator runs some
simple steps to manage the offline transitions.
We may have around 50 tapes in the library dedicated to TSM, of which only
about a half of a dozen are scratch tapes at any particular time. We're
upgrading from LTO 3's to 4's next quarter.