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Re: [Networker] Not all tapes are fully used
2006-08-16 09:36:58
Nico De Ranter wrote:
That's what I meant. If Networker somehow decided the tape isn't worth
writing it should flag it as bad (and of course move on to the next
tape) so the next time it won't be reused either.
The problem with doing that is that NetWorker doesn't know why the error
occurred. It could be a bad tape, or a drive problem, or a SAN or SCSI
problem. If it refused to re-use a tape after every SCSI error no matter
what the cause you would accumulate a LOT of bad tapes.
Unfortunately I cannot find anything in the logs that would indicate why
it's giving up on the tape. However the following message keeps popping
up every once in a while (but NOT for all tapes that have only been
partialy used):
daemon.001:08/10/06 13:13:06 nsrd: media notice: Volume "4640" on device
"/dev/rmt/5hbn": Block size is 32768 bytes not 65536 bytes. Verify the
device configuration. Tape positioning by record is disabled.
Shouldn't the block size depend on the device, not the tape? In that
case why doesn't he complain about this for *every* tape?
This almost certainly doesn't mean that your block sizes are wrongly
configured. It means that NetWorker has tried to read a block and has
read something that it does not understand.
Can I safely change the block size settings without invalidating all my
existing tapes (the manual seems to suggest that's not possible)
No - you don't need to change your block sizes, they are probably not wrong.
Just as an aside, you mentioned in your original post that you get 105GB
on an LTO-1 tape and this post shows you are using the hbn device. You
could get much better performance both in terms of speed and capacity by
using the cbn (compressed) device. You may typically get twice as much
or even more on each tape depending on the data you are backing up.
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