Re: [exim] Exim4 and SA: Overloading the system

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Szerző: Patrick von der Hagen
Dátum:  
Címzett: exim
CC: users
Tárgy: Re: [exim] Exim4 and SA: Overloading the system
Bill Hacker wrote:
[...]
> The volume, type, and size of messages and attachments, (spam and
> genuine) is more important than user-count.

Have a look if your mail-throughput has increased since activating SA.
There have been reports where someone disabled recipient verification
when activating SA, thus accepting messages for invalid recipients,
performing lots of work (SA, antivirus) and bouncing later. That would
certainly waste lots of recourses and personally I consider such a setup
to be quite impolite....

>
> The number of SA (and other, CLAMAV, for example) tests, and where htye
> are being applied.

Especially: running Bayes? Running AWL? I'd consider disabling those
tests if recources are low. How do you run SA? Are you actually calling
spamassassin using a "sandwich-setup", do you at least run spamc/spamd
(much better) or do you run exiscan or sa-exim (IMHO those are probably
the best ways to run SA). Or is some kind of amavis involved?

[...]
> You might want to start by isolating what processes are using what
> percentage of resources.....

E.g. run top, have a look which processes use your CPU, which processes
use your memory... do you swap? Is your CPU idle or running at 100%?
What about iowait?


PS: more RAM usually is a good idea but situations have been reported,
where adding memory just killed performance, so be careful with such
generalizations. There have been Intel-mainboard-chipsets with
2nd-level-caches supporting up to 256MB. Adding more memory gave you
more memory, sure. But disabled your 2nd-level-cache.....


-- 
CU,
    Patrick.