Re: vm issues on sap app server

From: Rik van Riel (riel@imladris.surriel.com)
Date: Wed Feb 19 2003 - 18:08:01 EST


On Wed, 19 Feb 2003, Dejan Muhamedagic wrote:

> Both servers swap constantly, but the 2.4.20aa1 at a 10-fold
> higher rate. OTOH, there should be enough memory for
> everything. It seems like both VMs have preference for
> cache. Is it possible to reduce the amount of memory used
> for cache?

Yes, you can reduce the size of the cache above which the
pageout code will only reclaim cache and not application
data. To set the percentage to 10% (from the default 5%):

echo 1 10 > /proc/sys/vm/pagecache

> Finally, there's a third SAP app server, an RS6000 running
> AIX with the same amount of memory, which seems to be more
> stable under various loads.

In that case you're probably familiar with the cache size
tuning, since AIX has the exact same tuning knob as rmap ;)

kind regards,

Rik

-- 
Engineers don't grow up, they grow sideways.
http://www.surriel.com/		http://kernelnewbies.org/
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