On 28/02/11, John Drescher (drescherjm AT gmail DOT com) wrote:
> On Mon, Feb 28, 2011 at 5:33 PM, John Drescher <drescherjm AT gmail DOT com> 
> wrote:
> > On Mon, Feb 28, 2011 at 5:22 PM, Jeremiah D. Jester
> > <jjest AT u.washington DOT edu> wrote:
> >> Here's my output..
> >>
> >> #test write.
> >> [root@scrappy bacula]# mt -f /dev/nst0 rewind
> >> [root@scrappy bacula]# mt -f /dev/nst0 weof
> >> [root@scrappy bacula]# dd if=/dev/nst0 of=/dev/null bs=64512
> >> dd: reading `/dev/nst0': Input/output error
> >> 0+0 records in
> >> 0+0 records out
> >> 0 bytes (0 B) copied, 5.39927 seconds, 0.0 kB/s
> >>
> >> #/var/log/messages
> >> Feb 28 14:17:46 scrappy kernel: st0: Failed to read 65532 byte block with 
> >> 64512 byte transfer.
> >>
> > You will have to increase the block size since your tape was written
> > with a larger block size.
> >
> Also this is the expected output since you did not write anything to
> the tape after the weof. This was actually trying to read the tape not
> write.

John -- I'd be grateful for your comments on how best to do a dd based
read and write test for LTO3 and LTO4 tapes. This seems like a fairly
good way of narrowing down a drive or interconnect problem.

Is something like the following correct?

    mt -f /dev/nst0 rewind
    dd if=/dev/sd<x> of=/dev/nst0 bs=64512 count=10000 # about 300GB
    mt -f /dev/nst0 rewind
    dd if=/dev/nst0 of=/dev/null bs=64512 

Many thanks
Rory

-- 
Rory Campbell-Lange
rory AT campbell-lange DOT net

Campbell-Lange Workshop
www.campbell-lange.net
0207 6311 555
3 Tottenham Street London W1T 2AF
Registered in England No. 04551928

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