Joni, I suspect that, after the "Total Buffer Requests" hits a million or two, the statistics should report a better "Cache Hit Pct.". The more I/O to the database, the better the reported "Cache Hit Pct." should become - assuming a "normal" workload, access pattern, etc.
Also, is this server experiencing "poor performance" (since that should be your bottom-line concern), or are you just "wondering" at this point about this statistic? Regards, Mark -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] On Behalf Of Joni Moyer Sent: Thursday, January 20, 2005 9:26 AM To: [email protected] Subject: Fw: Cache Hit % below 99% I have looked at the TSM Performance and Tuning Guide and the System Memory on the TSM server is 4096MB. Since the table only went to 2048MB, I just doubled the amount of the recommended buffer pool size to 524288, which I assumed was in KB. It is still only in the 95% range, so that's why I'm a little confused as to why it isn't higher... Server Option Option Setting Server Option Option Setting ----------------- -------------------- ----------------- -------------------- CommTimeOut 60 IdleTimeOut 15 BufPoolSize 524288 LogPoolSize 1024 I looked at the message that the bufferpool size can't exceed 10% of physical memory. 10% of 4GB would be 419430 KB. 524288 KB > 419430 KB, but what occurs when it is higher? I didn't really see any info. on what happens if it is higher... Thanks again! PS Thanks for the link to that Performance Diagnosis presentation. I'm sure it will come in handy! ******************************** Joni Moyer Highmark Storage Systems Work:(717)302-6603 Fax:(717)302-5974 [EMAIL PROTECTED] ******************************** "Richard Sims" <[EMAIL PROTECTED]> To 01/20/2005 08:27 "Joni Moyer" AM <[EMAIL PROTECTED]> cc Subject Re: Cache Hit % below 99% Joni - See BUFPoolsize in ADSM QuickFacts. The TSM Performance Tuning Guide is your best basic reference in this area. Richard Sims On Jan 20, 2005, at 8:19 AM, Joni Moyer wrote: > Hello All! > > I have noticed that the cache hit % is below 99%. This is a newly > defined > TSM 5.2.2.5 server on an AIX 5.2 OS. Are there any special > parameters/definitions that could contribute to the percentage being so > low? Thanks! > > Available Space (MB): 24,576 > Assigned Capacity (MB): 19,484 > Maximum Extension (MB): 5,092 > Maximum Reduction (MB): 15,000 > Page Size (bytes): 4,096 > Total Usable Pages: 4,987,904 > Used Pages: 45,207 > Pct Util: 0.9 > Max. Pct Util: 0.9 > Physical Volumes: 3 > Buffer Pool Pages: 131,072 > Total Buffer Requests: 132,692 > Cache Hit Pct.: 95.15 > Cache Wait Pct.: 0.00 > Backup in Progress?: No > Type of Backup In Progress: > Incrementals Since Last Full: 0 > Changed Since Last Backup (MB): 0.73 > Percentage Changed: 0.41 > > ******************************** > Joni Moyer > Highmark > Storage Systems > Work:(717)302-6603 > Fax:(717)302-5974 > [EMAIL PROTECTED] > ********************************
