ADSM-L

[new] DB Cache Hit Rate Question

2003-02-19 22:07:45
Subject: [new] DB Cache Hit Rate Question
From: David le Blanc <David.leBlanc AT IDENTITY-SOLUTIONS.COM DOT AU>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Thu, 20 Feb 2003 14:07:00 +1100
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

<Prev in Thread] Current Thread [Next in Thread>