Hi,
On Tue, Oct 27, 2009 at 9:35 PM, Gšötz Reinicke - IT Koordinator goetz.reinicke@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