Re: [exim] Stress testing an smtp server

Hello wash,

Odhiambo G. Washington schrieb:
> I am looking for a tool that I can use to stress-test my SMTP server
> (Exim, of course). I simply want to load the server to an extent that
> would lead it to in turn stress the CPU and eat a considerable amount
> of memory...
> It's a production box, so I would not want mail to go out to anyone,
> except myself, if there was any mail to go out as part of the test.

From my experience, testing filesystem IO is a decent way to try to
come close to real-world capabilities. The rate in which your OS
handles TCP connections is nothing you can influence with hardware.
As long as you don't do extensive computation when handling email
filesystem IO is all that matters - and it's rather easy to benchmark.

Years ago we set up half the lab for "real world" smtp benchmarks (I
think it was an early exim 3 then) and I wouldn't do that anymore,
mainly because IO benchmarking - in our tests - lead to very close
results.

What I found helpful is to lock memory in order to minimize
filesystem caching beautifying test results. Adjusting the relevant
kernel parameter in your OS will do the job, too.

You did not mention if you do message parsing (for malware, viruses
and such). If you do, the above most probably would not apply anymore.

hth,
vt