Sascha,
This rule is for UNIX servers (AIX, Solaris, HP-UX). You can find where
the rule originates from - in redbook "Getting Started with Tivoli Storage
Manager: Implementation Guide" (SG24-5416-01) on p.270 you can find a
description
"Tivoli Adaptive Algorithm:
Tivoli Storage Manager can use the SELFTUNEBUFPOOLSIZE YES parameter in
the server options file to activate self-tuning. When you activate this
option, the server will check the cache hit ratio each time inventory
expiration is run. If the value is less than 98%, then it will increase
the BUFPOOLSIZE by a predictable factor related to the actual cache hit
ratio achieved. An upper limit for BUFPOOLSIZE with self-tuning is imposed
of 10% of the real memory for AIX, HP UX, Sun Solaris and Windows NT, and
50% of the region size in OS/390. If you still need a larger BUFPOOLSIZE
and it is acceptable in your environment, you will have to set the value
manually."
And because your question was about OS/390 TSM servers the correct answer
ought to be 50% of the TSM server region. If 49152k is 10% of the region
size then the correct answer probably is 245760k. Of course if 49152 is
10% of total memory of the mainframe then the region is smaller and
bufpoolsize must be too.
In fact you are achieving 97.7% with only 32 MB so 48 MB might be enough
to get over 98%. Many people on this list reported that
SELFTUNEBUFPOOLSIZE served them well and it might be worth to try it
yourself.
Zlatko Krastev
IT Consultant
Please respond to "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
To: ADSM-L AT VM.MARIST DOT EDU
cc:
Subject: Antwort: Re: cache hit rate
Hi,
an IBM Technician gave me the following rule:
bufpoolsize = 10% of your memory.
I think 49152 is ok ...
MfG
Sascha Bräuning
Sparkassen Informatik, Fellbach
OrgEinheit: 6322
Wilhelm-Pfitzer Str. 1
70736 Fellbach
Telefon: (0711) 5722-2144
Telefax: (0711) 5722-1630
Mailadr.: sascha.braeuning AT sparkassen-informatik DOT de
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