On Wed, 2005-03-02 at 11:30 +0100, Gerhard Schneider wrote: > On Sun, 2005-02-27 at 22:46 +0200, Kai Makisara wrote: > > > > > This shows that your application is not using very large block size (3 > > pages, 10 kB?). You might get better throughput with larger block size (32 > > kB or 64 kB is usually large enough). If the Megaraid command processing > > speed is not fast enough, this might explain the problem (not probable but > > I can't see any probable problems ;-) > > > > After different tries (I had problems w/ my backup schedule - ever tried > to back up 600 GB with 2.6MB/s? :-) > > Tape block sizes between 10k and a few MB don't make any difference > > For better understanding I did the tests with > > dd if=/dev/zero of=/dev/nst0 bs=1M and different mt setblk > > No chance to go above 2.6 MB/s >
Moved the tape drive to another machine w/Fusion chipset, but w/o
Megaraid controller. Absolutely the same software.
dd if=/dev/zero of=/dev/nst0 bs=1M count=1000
1000+0 records in
1000+0 records out
1048576000 bytes transferred in 24.597061 seconds (42630134 bytes/sec)
That's the transfer rate the tape drive is able when receiving bullshit
(/dev/zero).
It's a megaraid issue (not a tape issue..)
GS
changing all backup scripts to the new machine
--
Gerhard Schneider
Institute of Lightweight Design and e-Mail:[EMAIL PROTECTED]
Structural Biomechanics (E317) Tel.: +43 1 58801 31716
Vienna University of Technology / Austria Fax: +43 1 58801 31799
A-1040 Wien, Gusshausstrasse 27-29 http://www.ilsb.tuwien.ac.at/~gs/
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