>because I need legislative authorization here to stop and restart my TSM
server.


Geesh, and I thought that politics around my shop were bad!


                                                                                
                                                              
                      "Brian L. Nick"                                           
                                                              
                      <BRIAN.                  To:       ADSM-L AT VM.MARIST 
DOT EDU                                                                 
                      NICK@PHOENIXWM.          cc:                              
                                                              
                      COM>                     Subject:  Re: cache hit rate     
                                                              
                      Sent by: "ADSM:                                           
                                                              
                      Dist Stor                                                 
                                                              
                      Manager" <ADSM-                                           
                                                              
                      L AT VM.MARIST DOT EDU>                                   
                                                                     
                                                                                
                                                              
                                                                                
                                                              
                      08/22/2002 06:25                                          
                                                              
                      AM                                                        
                                                              
                      Please respond to                                         
                                                              
                      "ADSM: Dist Stor                                          
                                                              
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John,

 We were running into performance issues after upgrading the STM server to
4.2.1.15 and Tivoli suggested that bufpoolsize for us. I thought that it
was too large as well. What we were not doing, and still are not, is coding
a region parameter of 512M. We are using the old 0M parameter. I can't
change that right now because I need legislative authorization here to stop
and restart my TSM server. Looks like I'm stuck with the 0M region until
Saturday.





                      "John Naylor"
                      <john.naylor@SCOTTISH-SOUT         To:       ADSM-
L AT VM.MARIST DOT EDU
                      HERN.CO.UK>                        cc:
                      Sent by: "ADSM: Dist Stor          Subject:  Re:
cache hit rate
                      Manager"
                      <ADSM-L AT VM.MARIST DOT EDU>


                      08/22/02 05:29 AM
                      Please respond to "ADSM:
                      Dist Stor Manager"







I have almost the same as you
os390 2.10 and tsm database 18.5 gb used
I have region size at 512 m but my bufferpool is only 49152
I am seeing 98% plus cache hit, so I do not see where  bufpoolsize 225280
is coming from.





"Brian L. Nick" <brian.nick AT phoenixwm DOT com> on 08/21/2002 05:34:34 PM

Please respond to "ADSM: Dist Stor Manager" <adsm-l AT vm.marist DOT edu>

To:   adsm-l AT vm.marist DOT edu
cc:    (bcc: John Naylor/HAV/SSE)
Subject:  Re: cache hit rate




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We are working with Tivoli/IBM right now on an unrelated problem and they
have indicated to us that our cache hit should be above 98%.  We are in the
process of making changes to our region size to attempt to address this.
TSM server running on OS/390 2.10 db 37.8Gb 50% utilized. One thing that we
are being told is that a region of '0M' is not a good fit for TSM on this
platform. we are going to be testing region ' 512M ' bufpoolsize 225280.

 Our current cache hit % is 97.69.

 Brian


Brian L. Nick
Systems Technician - Storage Solutions
The Phoenix Companies Inc.
100 Bright Meadow Blvd
Enfield CT. 06082-1900

E-MAIL:  Brian.Nick AT phoenixwm DOT com
PHONE:   (860)403-2281




                      "KEN HORACEK"
                      <KHORACEK@INCSYS         To:
ADSM-L AT VM.MARIST DOT EDU
                      TEM.COM>                 cc:
                      Sent by: "ADSM:          Subject:  Re: cache hit rate
                      Dist Stor
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                      <[email protected]
                      T.EDU>


                      08/21/02 12:18
                      PM
                      Please respond
                      to "ADSM: Dist
                      Stor Manager"






No experience.  I fact I'm learning from your experience.  While you say

"from my training at IBM that a cache hit rate of 99% and above is
recommended"

I found the following statement in the web interface.

The server database performs best with a cache hit ratio above 97% in the
database bufferpool. To tune the bufferpool size, (a) reset the bufferpool
statistics, (b) execute server operations that use the database, and (c)
view the database details to see if the cache hit ratio is above 97%. If
the cache hit ration is NOT above this percentage, increase the size of the
BUFPOOLSIZE specification in the server options file.

Conflicting advice?  Perhaps your 97.7% is good and no problem exists.
Let's hear from others.  Please......


Ken
khoracek AT incsystem DOT com


>>> Sascha.Braeuning AT SPARKASSEN-INFORMATIK DOT DE 08/21/2002 12:46:04 AM >>>
Hi all,

first I've to thank all participants for the amount of answers I got on my
latest questions. Now I've got a new one which relates on the
bufferpoolsize and the cache hit rate on OS/390 TSM-Servers.

we use the following bufpoolsize:  32768
our chache hit rate:            97,7 %

I know from my training at IBM that a cache hit rate of 99 % and above is
recommended. Is it possible, that a lower cache hit rate can cause
performance-problems? What is your experience?


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