Debugging system load - How to start?

Götz Reinicke - IT-Koordinator goetz.reinicke at
Tue Oct 27 08:50:57 GMT 2009


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.

I was planing to exchange the server respectively distribut the services
in the near future anyway, but I'm interessted in what causes the load
now or where the system "hangs" :-)

There is a lot of work to do and the setup is not very well designed,
but at the time I started the mailsystem at our place, I had only this
one server and a lot of user requests ...

The System:

Intel Pentium D 3.20GHz, 8 GB RAM, 3Ware 4*320GB Sata II Raid Level 5,
Gigabit LAN.

Red Hat EL 5.4 (still 32 Bit)

About 700 Users, 1GB Mailboxquota (mbox), Webmail-System Horde, an
avarage of 3.200 messages per day over the last 12 Month.

The Services and setup:

Dovecot imap(s) & pop3(s), mailscanner, spamassassin, mysql, bind,
httpd, sendmail.

Because there are so many config parameters I'll summarise this a little

Mails are checked agains two blacklists ( and Spamhaus) by
sendmail, mailscanner and spamassassin use mostly the default settings.
Virusscanning is done by avira AV.

Logging for mailwatch to mysql is activated.

What tools or logfiles may give me a clue which settings should be
checked or changed?

Thanks and best regards,


Götz Reinicke

Tel. +49 7141 969 420
Fax  +49 7141 969 55 420
E-Mail goetz.reinicke at

Filmakademie Baden-Württemberg GmbH
Akademiehof 10
71638 Ludwigsburg

Eintragung Amtsgericht Stuttgart HRB 205016
Vorsitzende des Aufsichtsrats:
Prof. Dr. Claudia Hübner
Staatsrätin für Demographischen Wandel und für Senioren im Staatsministerium

Prof. Thomas Schadt

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