I have experienced similar issues with tape duplication (disk stu to
tape duplication works like a charm...).  My DLT7k's were dup'ing in the
hundreds of KB/sec, not exactly conducive to mass duplication.

I spoke with Veritas support and, after numerous logs again, got a few
parameters to change but they did not seem to help.  Primarily buffer
settings; size and number.

I would very much like to hear from other people if they have tape dup's
working well and what their settings are.

~JK

Eric Forgette wrote:
> 
> I wrote a perl script to duplicate the most recent, successful, full
> backup images for a particular class.  The script is available at
> http://perlvault.sourceforge.net/ (beta release still...)
> 
> The problem I am having is in the performance of the image copies.  My
> expectation was that the tape to tape copies would be faster than the
> backups themselves.  The regular backup performance is limited by the
> fact that there are tons of small files and by the network speed / cpu
> speed of the client.  My understanding is that the images (once on tape)
> are one sequential file, which should lend itself well to copying.
> 
> The master is an E4500 running Solaris 5.8.  I am using LTO drives which
> are SAN attached.  I've seen throughput (using iostat) of 11 MB/second
> during regular backups.  During the image copies, I get between 5 - 7
> MB/second.  The regular backups do not use any multiplexing.
> 
> Is there any tuning parameters I can tweak?
> Anyone have any ideas?
> 
> Regards,
> -Eric
> --
> Eric Forgette
> Unix Systems Administrator
> _______________________________________________
> Veritas-bu maillist  -  Veritas-bu AT mailman.eng.auburn DOT edu
> http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu

-- 
=====================
Jeff Kennedy
Unix Administrator
AMCC
jlkennedy AT amcc DOT com