[EMAIL PROTECTED] wrote on 06/07/2006 04:07:09 PM:

> * Resizing seems to have pretty much resolved our batch processing but
> hasn't helped online activity. Udtmon still shows a surprising amount 
over
> Overflow 2 activity. We're investigating, so maybe we have more work to 
do
> there. Does anyone know what a system in overflow 2 looks like to the 
O/S?
> Maybe a higher number of reads?
> 
> It seems as if there is a bottleneck that noone can identify. Aside from
> periodic AIX read/write waits nothing shows any problems.

Level 2 overflow will most likely manifest itself in terms of additional 
I/O requests at the O/S level.  Look at the "heavy hitters" list in 
filemon.  If there's a file at the top of the list, and the number of 
reads seems high, check sizing on that file.

You say that batch processing is OK but interactive users are experiencing 
performance problems.  Is this constant or intermittent?  I wouldn't be 
surprised to hear that some users experience long delays while others fly 
through.  Does the wait queue (see sar -q or topas) show high values?  I 
would look at random write-behind and maybe high- and low-water marks for 
possible relief.

There could be a complex combination of events - at the database and/or 
AIX levels - converging to create these problems.  <Shameless plug alert!> 
 You may want to have somebody perform a detailed health check of your 
system.  I may just know of somebody who could help you out with this. ;-)


Tim Snyder
Consulting I/T Specialist , U2 Professional Services
North American Lab Services
DB2 Information Management, IBM Software Group
717-545-6403
[EMAIL PROTECTED]
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