Veritas-bu

[Veritas-bu] Storage Tek Drives

2002-05-24 06:55:37
Subject: [Veritas-bu] Storage Tek Drives
From: spe08 AT co.henrico.va DOT us (Spearman, David)
Date: Fri, 24 May 2002 06:55:37 -0400
We have 9840A drives on site. The 9840a has a 64kb internal buffer. It has
been our experience that any thing over 64kb buffers set in nbu will cause
error 14's (at a minimum). Best bet with the A's is to back off buffer size
(also receive buffer) to 64kb. If you get waiting for buffers this is one of
those cases where you will want to increase num_buffers. However, the 9840a
while a good tape unit has never shown the kind of throughput as advertised,
especially in a mixed invironment of MS / Unix old / new machines. I have
not had a chance to check out the B variant. The installation manual should
include specs on the internal buffer. If you find a way to make their system
scream let me know.

David Spearman
County of Henrico, Va.  

-----Original Message-----
From: David A. Chapa [mailto:david AT datastaff DOT com]
Sent: Thursday, May 23, 2002 5:16 PM
To: Veritas NBU_Q&A
Subject: [Veritas-bu] Storage Tek Drives


The drives: 9840a's and b's

A client installed a new media server, ran some test backups and was
disappointed with the results.  We looked at how it was configured and I
mentioned that he may want to increase the buffer size to 256K.  They did,
but now can't restore the data from the previous backups that were done at
the default block size.

I am almost positive I have had customers tweak this value up and down
without sacraficing their abilities to do restores (DLT mostly).

Is this typical of the 9840 drives?

If so, my alternative plan is going to be to

1. duplicate the images from the new media server to the master server.
2. bpexpdate images on the new server
3. duplicate these images on the master to meet their DR level.

is there a better idea?

David

<><><><><><><><><><><><><><><><><><><><>
David A. Chapa
NetBackup Consultant
DataStaff, Inc.
http://www.datastaff.com
847 413 1144
---------------------------------------
http://www.NetBackupcentral.com

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