Have you downloaded the tuning white paper from the support.veritas.com
site yet?

Microsoft recommends the NET_BUFFER_SZ to be 129, for optimum speeds of
backup and duplication.

I found the link to VERITAS' size that explains this.

http://seer.support.veritas.com/docs/244083.htm

While this tech note reference SDLT, I believe the text regarding
Microsoft is accurate still.

David A. Chapa * Technical Advisor, Technical Marketing * ADIC *
720.249.5836 * david.chapa AT adic DOT com

Pathlight VX - Integrated Disk-to-Tape Backup - http://www.adic.com


-----Original Message-----
From: Karun Subramanian [mailto:karunanidhis AT hotmail DOT com] 
Sent: Wednesday, January 14, 2004 7:25 PM
To: Veritas-bu AT mailman.eng.auburn DOT edu
Subject: [Veritas-bu] Windows backups running slow Netbackup 4.5 FP3 !

Hi Folks !
I have a Sun V480 Media Server connected to a IBM LTO 3584 library with
6 
tape drives.
My unix backups are running fast enough.
But Windows clients backups are running slow. The strange thing is when
I 
run one job, it runs faster. But as I start more Windows backup jobs,
the 
speed of induvidual backups reduce gradually. If I run 4 jobs 
simultaneously, each job runs at 1/4th of its original backup speed. The

unix jobs are running just fine. The Windows clients are in a different 
subnet but there are no routers in between. When I start killing the
backup 
jobs, the active jobs gradually speed up.

6 drives are connected to 3 SCSI controllers.

My Buffer parameters are,
NET_BUFFER_SZ = 256 KB
SIZE_DATA_BUFFERS = 64 KB
NUMBER_DATA_BUFFERS = 64

Any idea ???

Thanks.

_________________________________________________________________
Check out the new MSN 9 Dial-up - fast & reliable Internet access with
prime 
features! http://join.msn.com/?pgmarket=en-us&page=dialup/home&ST=1

_______________________________________________
Veritas-bu maillist  -  Veritas-bu AT mailman.eng.auburn DOT edu
http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu