Re: vm issues on sap app server

[Dejan Muhamedagic <dejan@hello-penguin.com>]

Rik,

On Wed, Feb 19, 2003 at 08:08:01PM -0300, Rik van Riel wrote:
> On Wed, 19 Feb 2003, Dejan Muhamedagic wrote:
> 
> > 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

Will that work with rmap15d?  The code seems to support only min
and borrow parameters.  Correct me if I'm wrong.  This is what it
looks like currently:

# cat /proc/sys/vm/pagecache
1       3       20
# mem | grep Cache
Cached:        4569128 kB
SwapCached:     829668 kB
ActiveCache:    136728 kB

> 
> > 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 ;)

AIX vmtune -P is equivalent to the Linux cache-max, but cache-max
is not implemented.

Cheers!

Dejan