I just changed my settings to 262144 for both of these.  Previously they
were set to 65536.  We'll see how that works once I can restart the
daemons.

~JK

> "Donaldson, Mark" wrote:
> 
> Check your buffer settings - this made a difference for me.  See this
> tech note:
> http://seer.support.veritas.com/docs/183702.htm.
> 
> Having my NET_BUFFER_SZ set the same as my SIZE_DATA_BUFFERS made a
> measurable difference in my duplication speed.
> 
> Also, consider the source images.  If they're muliplexed then the
> desired image must be sorted from the undesired blocks resulting in
> slower copies.
> 
> HTH - Mark
> 
> -----Original Message-----
> From: Eric Forgette [mailto:epforgette AT overnite DOT com]
> Sent: Wednesday, August 28, 2002 9:15 AM
> To: veritas-bu AT mailman.eng.auburn DOT edu
> Subject: [Veritas-bu] tape drive performance on image copies
> 
> 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