Re: [Exim] exim performance

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Author: Richard Welty
Date:  
To: exim-users
Subject: Re: [Exim] exim performance
On Wed, 23 Oct 2002 11:00:07 +0400 (MSD) Alexander V Alekseev <alex@???> wrote:
> >         The program indicates that Exim can handle only 5 mes/sec! ;(
> > (200 mes/40s).
> >         This is so bad.
> >         What I can do to improve this number?
> >         I' m atacching the exim.conf too.
> >         Much thanks,                Paulo Henrique


>         Just like my testing configuration. The only difference, I used
> latest exim-4.10 (btw: why did you use 3.35?). My testing program was
> written on expect. So, a few ideas:


> 1. Exim spawns new process very often. So, you need enough memory. I
> suppose, you should start with 1Gb. (In my case, each exim eats about
> 8Mb RAM).


yes, ram is good

> 2. Mail goes in parallel. So, you should be able to accept it and
> deliver. May be you should increase queue_run_max (default 5, I suppose
> something like 100 should be reasonable).


remote_max_parallel is your friend. i run it at 40, more is probably ok.

> 3. Exim enques mail much faster, than delivers. (I suppose, about 3
> times). So, you need to benchmark delivery speed and enqueue speed.


> 4. When testing, do parallel SMTP delivery. I tried 20 parallel requests
> per 500 e-mail each. This shows better speed.


> 5. With 4.10 I could do up to 90 enques/30 deliveries per second. But
> not more. CGP does about 1000 enques and 100 deliveries on such hardware.
> It looks strange.


where is your DNS being done? DNS delays is a common problem. install a
caching, recursive DNS server on the mail machine, or on a machine on a
nearby subnet, and have the exim server use it.

also, depending on circumstances, split_spool_directory may help. disk i/o
blocking is another potential problem for an MTA.

richard
--
Richard Welty                                         rwelty@???
Averill Park Networking                                         518-573-7592
              Unix, Linux, IP Network Engineering, Security