SIZE_DATA_BUFFERS helps optimize backups when used to match the recommended
block size for your tape drive.  Depending on your drive technology it may
be 64k or 128k.  The SIZE_DATA_BUFFERS is visible in your Media Contents
report under the Block Size column.  The NUMBER of these buffers depends
upon your server's available memory.  (sorry, I don't have any ideas on your
NT client errors)

Doug Braden
VERITAS Impact Team



-----Original Message-----
From: Jim VandeVegt [mailto:vandevegt AT yahoo DOT com]
Sent: Monday, December 18, 2000 1:00 PM
To: NetBackup Veritas
Subject: [Veritas-bu] NUMBER_ & SIZE_DATA BUFFERS


Can other readers share what your NUMBER and SIZE_DATA_BUFFERS are in
/usr/openv/netbackup/db/config?

My master server is a Sun 450, 1 GB RAM, 2x 400 MHz processing. 
Shared Memory MAX is set to 1GB in /etc/system. Six tape drives.

I recently noticed my backups were going pretty slow and I realized I
didn't have these two files in place, thus I was using the default
8x32KB buffers. I remembered from my NetBackup class that almost
everyone increases the size of the buffers and usually decreases the
numbers, but maintains a great increase in the total size of the
buffer (size times number).

I tried 4 buffers 1048576 bytes (2^20 = 1 MB) big. I noticed a
speedup in backups, but some NT clients started throwing errors.

Most of the errors are 174, a media manager error, which doesn't make
a lot of sense; and a few error 41 (network connection timeout).

But I haven't fully diagnosed the errors net in the log files. I'm
more interested in what other installations use for the buffer settings.

=====
Jim VandeVegt
vandevegt AT yahoo DOT com vandevegt AT avaya DOT com
http://members.xoom.com/vandevegt
Toilet paper should come off the front!

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