database cache hit ratio too low

[tsmuser13]

hi friends

today i got this message in my tsm report

'Database Cache Hit Ratio is too low'

its says the following value 97.8<98 in condition column and under recommended action it says in the report to increase the buffer pool size.


please could you tell me how should i increase the buffer pool size and do i need to stop the tsm server while increasing this value.

Please help.

thanks in advance.

 

[vamsi]

Hai tsmuser13

u need not stop the tsm server

just go to d cmd line and giv this cmd

setopt bufpoolsize 262144

 

[tsmuser13]

query

hi vamsi

many thanks for your prompt reply but now i am checking the command
'q db f=d' and i get the following output

Available Space (MB): 20,000
Assigned Capacity (MB): 19,000
Maximum Extension (MB): 1,000
Maximum Reduction (MB): 9,908
Page Size (bytes): 4,096
Total Usable Pages: 4,864,000
Used Pages: 726,241
Pct Util: 14.9
Max. Pct Util: 17.4
Physical Volumes: 4
Buffer Pool Pages: 32,768
Total Buffer Requests: 6,218,225
Cache Hit Pct.: 98.88
Cache Wait Pct.: 0.00
Backup in Progress?: No
Type of Backup In Progress:
Incrementals Since Last Full: 0
Changed Since Last Backup (MB): 88.91
Percentage Changed: 3.13
Last Complete Backup Date/Time: 04/13/10 17:55:13
Estimate of Recoverable Space (MB):
Last Estimate of Recoverable Space (MB):


which means that cache hit pct is 98.88, so do i still need to increase this value or should i wait another day and observe the cache hit ratio.

why does this message come.

please help..

thanks again.

 

[vamsi]

Hai

Increasing will improve ur server performance

its ur wish 2 increase r not

just check for another day still if u find any problem just increase it

Regards,
Vamsi

 

[fuzzballer]

You should watch this over several samplings throughout the day and see how it is doing. I have servers that give me that message everytime they get rebooted. The rest of the time they are above the 99% range. The recommendation is 10 to15% of actual memory. The size recommended by Vamsi is standard for most setups. Be careful not to set it so high the server starts paging. Some of mine are set to 524288 and others are at 262144. Hope that helps. You can find this in the Administration Performance and Tuning Guide.

 

[tsmuser13]

thanks vamsi

problem is solved with your help.

many thanks.

 

[tsmuser13]

thanks fuzzballer for your help.

the problem is solved.