Ronny Vaningh wrote: > Hi
>
> I want to persuade my boss to migrate our mailsystems to exim.
>
> I tried to stress test my mailserver running 4.12.
>
> The hardware is a dual P3 XEON700 with 1 GB of RAM
> RAID1 message spool and separate RAID1 system/log partition on 10Krpm
> scsi disks.
>
> This hardware should normally be able to cope with some load.
>
> The current setup is pretty straightforward:
>
> standard rcpt acl
> smtp_accept_max set to 200
> split queue
>
> However when I start putting more than approx 70 simultaneous smtp
> sessions against the box the load starts killing my machine ranging up
> to loads of 200 and 100% CPU usage.
>
> It seems that it`s not capable of handling all the deliveries.
>
> I tried running queue only with a few queue runners.
>
> Mail took longer to get out but load levels were acceptable.
>
> Do you have any sugestions how to set up a box so that it would be able
> to process around 120K messages per hour (15Kb-30Kb).
How you handle your domains, what kind of database do you use?
Do you run a local caching-daemon?
What OS do you run?
What filesystem do you use?
Do you want to do normal mail-delivery or mainly mailinglists/newsletters?
Do you test remote or local delivery?
The "problem" is that exim tries to send out mail as soon as possible,
in fact it starts the delivery in the moment it sends back the 2xx OK
for the DATA.
A good way to cope with this is to set queue_only_load to a reasonable
value and use a queue_runner_max of 20 or so, then set you queue-runner
to 1 or 2 minutes. That will slow down the delivery a bit, but it also
will regulate the amount of running exim-processes. Tuning these values
should help to get the best out of the machine.
Tell us more about your current setup/config and we can tell you more
about what to do.
