I am in agreement with Ed,
We could backup to disk ok, but getting it of disk to tape took longer
and we could not get it finished before the next nights backups, and
that was when we had SDLT tape drives.
I now have LTO4 drives and backup straight to tape and I still cannot
keep all the tape drives busy.  So just did not work for us.
There are times it is needed. 
Some backups, like if you want to do exchange where you can restore just
one email, needed the backup to be on disk, you could not do that from
tape.  So you have to look at what kind of backups and restores you do
and if you need the backup on disk to so the restore.

-----Original Message-----
From: veritas-bu-bounces AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of Victor
Engle
Sent: Sunday, April 25, 2010 2:15 PM
To: veritas-bu AT mailman.eng.auburn DOT edu
Subject: [Veritas-bu] Architectural question (staging)

Hello List,

Just wanted to get some opinions about whether disk staging units are
worthwhile. My backup server has two BasicDisk staging units with the
storage units configured such that the data goes to disk and is then
moved to tape. I have a tape library with four LTO-3 drives connected
via FC. So what I'm wondering is, since the LTO drives are reasonably
fast, and since I'm writing the data ultimately to tape anyway, would
it be better to just write directly to tape. The disk is just old
fashioned spinning disk with no de-duplication so there are
operational costs for the disks. All tape and disk storage units are
local to the backup server. I'm thinking it would be better to add LTO
drives and eliminate the disk for now and maybe later add a
de-duplicating disk unit.

Under what circumstances does it make sense to stage data on disk. I
would appreciate hearing what your thoughts and experiences are with
regard to disk staging.

Thanks,
Vic
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