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:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Joni Moyer
Sent: Thursday, January 20, 2005 9:26 AM
To: ADSM-L AT VM.MARIST DOT EDU
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
joni.moyer AT highmark DOT com
********************************



             "Richard Sims"
             <rbs AT bu DOT edu>
                                                                        To
             01/20/2005 08:27          "Joni Moyer"
             AM                        <joni.moyer AT HIGHMARK DOT COM>
                                                                        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
> joni.moyer AT highmark DOT com
> ********************************