Hi, On Tue, Oct 27, 2009 at 9:35 PM, Gšötz Reinicke - IT Koordinator <goetz.reinicke at filmakademie.de> wrote: > we run an "old" mailserver system which was set up a couple of years > ago. The systme dose "everything" what we need(ed). Over the last days I > noticed an unnormal increase of the system load up to 10 and lots of > users told me that there mailclient connections (sending and receiving) > are dropped from time to time. Try running Nmon over a couple of days collecting stats every 10-20 seconds (a bit excessive) or a minute. Then run the nmon stats through the Nmon Analyser spreadsheet. That should show how the I/O, RAM and CPU usage and top CPU consumers during those periods pretty nicely. Download Nmon for RHEL (perfectly usable on CentOS) from IBM or sourceforge : http://www.ibm.com/developerworks/wikis/display/WikiPtype/nmon , http://nmon.sourceforge.net/pmwiki.php and the analyser is here: http://www.ibm.com/developerworks/wikis/display/WikiPtype/nmonanalyser Here's a sample on how to run: #Intensive, every 10 second. Will use a lot of CPU nmon -fT -s 10 -c 8640 #Regular, a sample every minute nmon -fT -s 60 -c 1440 -- Hakan (m1fcj) - http://www.hititgunesi.org