ADSM-L

OS390 TSM Performance questions.

2003-02-12 10:48:11
Subject: OS390 TSM Performance questions.
From: Alan Davenport <Alan.Davenport AT SELECTIVE DOT COM>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Wed, 12 Feb 2003 10:46:23 -0500
Hello,

        We're running TSM v5.1.5.4 on an IBM 20660A2 processor running OS390
v10. There is a 100Mbit, single port OSA card on the processor. We are
backing up 197 clients per night. MAXSCHEDSESSIONS is set to allow 116
simultaneous backup sessions. Our backup window begins at 20:00 and ends at
07:30 the next morning. We are seeing poor performance on our backups during
the window.  For example, one server that will backup in 6-7 minutes outside
the window takes hours to complete during the window. The TSM server has a
region size of 1280M and MPTHREADING is set to YES. Self tune buffer size
and TXN size is enabled. We are backing up to a 100GB disc buffer to an EMC
model 8830 drive array. On average we backup 30-40GB per night with a peak
of 75-80GB.

        I know there are much larger shops backing up many more servers out
there running OS390 also. What I would like to know is, on large shops, what
is your OSA configuration? Are you running multi-port OSAs and/or gigabit
cards? For comparison, I would also like to know how many clients you are
backing up per night. Where do you think the bottleneck is? Have you seen
similar problems and what did you do to help alleviate the problem? I am
fairly confident that TSM is not CPU constrained during the window. We
recently moved TSM to a higher service class with little effect on the
problem.  Do you feel we are saturating the OSA card?

        Any thoughts and suggestions would be greatly appreciated.

          Take care,
               Al

Alan Davenport
Senior Storage Administrator
Selective Insurance Co. of America
alan.davenport AT selective DOT com
(973) 948-1306



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