[H-GEN] Tape Drives
gjb at gbch.net
Thu Jan 10 02:35:31 EST 2002
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(I sent this message out yesterday but have not seen it.
Apologies to anybody who gets to see it twice.)
Jason Henry Parker wrote:
| Bruce Campbell <bc at humbug.org.au> writes:
| > Decide whether you want speed, long-term reliability or small tape usage.
| > Two of these at the same time is usually not attainable ;)
Actually, I think you can have the first and third of these
together; I doubt if "long-term reliability" and "tape" belong
in the same sentence.
| Long-term reliability is a bit of a worry, though. How would I
| reasonably go about testing it? While I've never had a tape fail:
Seriously, for long-term storage, spinning disks are the best
bet. Tapes are good for disaster recovery, but not for archival
purposes -- just storing tapes for some time can result in bits
falling off the media.
I have some rules with tape. When I open a box of tapes, I
label each of the tapes with a batch number. When I get a
single error from a tape, I destroy all the tapes in that batch
(after restoring or replacing any data they are holding). I
maintain a label at the start of each tape which records a count
of uses and I throw the tapes away after a predetermined number
which varies according the tape type (50 for DDS-3). I also
destroy tapes once 3 years has passed since they were first
| (a) I've not had much call to use them, and getting enough time to
| run verifies every day is a bit much. I suppose I could test one
| tape per slightly-less-than-the-dumpcycle.
You need to verify them often enough to know that they are OK or
else your whole disaster recovery plan can turn to dust. I
don't do full restores for this -- I note which file gets dumped
last and restore that. It's not foolproof, but it's good enough
for my purposes as I always have several copies of all important
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