If this is a dedicated AIX machine set vmtune maxperm to 20 and minperm to
10 otherwise paging will start happening.

Paul D. Seay, Jr.
Technical Specialist
Northrop Grumman Information Technology
757-688-8180


-----Original Message-----
From: David le Blanc [mailto:David.leBlanc AT IDENTITY-SOLUTIONS.COM DOT AU]
Sent: Wednesday, February 19, 2003 10:07 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: [new] DB Cache Hit Rate Question


Hi Guys!

In following this thread, I thought I'd check out customer experience with a
stock TSM server they have.

q db f=d  showed the DB hit rate at 85%

q opt     showed the bufpoolsize at 2350

This was with auto tuning.

After disabling auto-bufpool tuning, I increased the bufpoolsize to 131072
(on a 2G system also running one other application) and notices the hit rate
climb to 99.2% over the next two days.

VMstat shows 'avm' of around 260000 pages, or just over
a GIG.  I therefore _assume_ the remainder constitutes buffer-cache.

vmstat showed absolutely no paging for the period I monitored (about 6 hours
during a working day), so would it be safe to further increase the
bufpoolsize?


Also, the customer noticed a TSM db backup which took 35 minutes two days
ago, now completes in 12 minutes. Could that indicate a problem?

TIA
Dave