[Mimedefang] really high cpu

James Ebright jebright at esisnet.com
Tue Feb 1 16:16:34 EST 2005

Solaris just is not the best platform for running sendmail on, I have 
experience with E-450 boxes (as well as ultra-sparcs) running Solaris 8 (top 
end solaris at the time) and honestly, I could bring that beefy box to its 
knees just by running billing and letting the little pentium 300 pump out the 
20,000 or so messages one after another... Linux on the other hand on a 
modest dual processor 500 MGhz, 512MB ram hardly broke a sweat. (typical pc 
server back then, also both boxes ran external raid, copper fibre channel)

The Solaris box constantly ran a load of 4-6 (4 processors, so this wasn't 
too terrible) but spam runs could shoot the load up over 30.

The Linux box ran with a load of 1-2 (2 processors so again.. not terrible, 
but better than Solaris) and spam spikes shot the load up to 4-8...

The difference I think is the OS and not hardware as we ran a few ad-hoc 
tests using the intel version of Solaris and found similar yet more 
pronounced results. We never did try Linux on the E-450s as they were all 
production boxes.

My regional network had 56,000 customers with 1-4 email accounts each, 
company wide we had nearly half a million customers with probably well over a 
million email accounts, we eventually moved off Solaris for email services 
and I have no idea what these customers or Earthlink uses now (because I 
haven't cared to look!)

So, if you are stuck with Solaris... get out the bat book and optimize 
sendmail as much as you can, local DNS caching deamon helps alot as does a 
small as possible local host file. Try and avoid gigantic passwd files too, 
NIS+ can help there. Turn off NFS and NFS automounters if possible. Tune the 
disk IO as much as possible, if I remember right Solaris was optimized for 
very large files, which mail is typically not. Play with tyhe nice level for 
mimedefang.  And if that all fails, yeah, you may need to up your hardware.

If you are not stuck with Solaris.... you might want to benchmark a modest 
linux box.. you may be surprised.. esp with the 2.6 kernel.

Also, load is a MUCH better indicator than %used on a processor, especially 
in multi-processor systems as you have to factor in nice levels, system idle% 
user levels, and several other factors that load factors in. If this box is 
ONLY used for mail then load should be your primary metric.


On Mon, 31 Jan 2005 14:08:17 -0800 (PST), Stephen Ford wrote
> mimedefang is using ~45% of my cpu which has me scared
> since there isn't any mail running through the box
> except mine and I'm suppose to use this box for the
> campus staff of over 1000 employee's in a few weeks. 
> I'm not getting much of a delay when I send mail that
> isn't spam (less then a second) and spam is delayed
> for ~10 seconds.
> I'm running Solaris 9 with 2 gigs of ram.  I have
> /var/spool/MIMEDefang in a 1 gig swap partition.  I
> installed the newest mimedefang this afternoon and the
> newest spamassassin last Friday through CPAN.  I took
> out the blacklist and uriblacklist which brought the
> box to it's knee's but it wasn't doing that when I was
> running spamassassin 3.0.
> Any suggestions before I throw this on a bigger box?
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