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#1 (**permalink**) 01-05-2008, 10:27 AM

I've recieved an LTO3 tape of data from a customer that's been written
with tar, I've determined the block size on the tape is 10240. (Which I
find quite odd.....)

Sadly my 3582 is attached to another system and I will not be able to
locally attach it to the target server for this data (about 400gig) I
have a gig network between the two servers, and have been attempting to
do the restore with the followign command.

LTO3 drive is set to variable block size.

>From the target server:

mytarget:# ssh -l ktelep tapeserver "dd if=/dev/rmt0 ibs=10240
obs=4096k" | tar -xvf -

Performance on this restore is less than expected. I can restore
sysback tapes with this same amount of data in 1/4 of the time. I'd
like to point fingers at the odd blocksize (I've alwaysed used 256k for
LTO3 backups) but I'd like to be sure.

Any suggestions on how to speed up this restore?????

Kurt

#2 (**permalink**) 01-05-2008, 10:27 AM

ktelep@gmail.com wrote:
> I've recieved an LTO3 tape of data from a customer that's been written
> with tar, I've determined the block size on the tape is 10240. (Which I
> find quite odd.....)

How did you determin this block size? Were you just looking
at the boundry for the fist block? If so you may be guessing
wrong, since there's also the chance of the tape being written
with variable block size.

Regards,

Frank

#3 (**permalink**) 01-05-2008, 10:27 AM

I actually looked at a number of blocks across the tape, from the first
block, the 10th block, even went out and skipped 100000 blocks to see
what the block size was, everything comes up 10240.

Frank Fegert wrote:
> ktelep@gmail.com wrote:
> > I've recieved an LTO3 tape of data from a customer that's been written
> > with tar, I've determined the block size on the tape is 10240. (Which I
> > find quite odd.....)
>
> How did you determin this block size? Were you just looking
> at the boundry for the fist block? If so you may be guessing
> wrong, since there's also the chance of the tape being written
> with variable block size.
>
> Regards,
>
> Frank

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Remote restore of tar tape