Re: [exim] Exim and Postfix

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Szerző: Heiko Schlittermann
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Címzett: exim-users
Tárgy: Re: [exim] Exim and Postfix
Eliza via Exim-users <exim-users@???> (Mi 28 Aug 2019 11:19:37 CEST):
> If exim supports runtime configuration, it becomes more flexible, for
> content filter etc. But how about the performance to accept/deliver messages
> comparing to postfix?


It depends on the workload you expect. If you've full queue (say 10⁶
messages), the Postfix queue manager will probably outperform Exim, given
you have the CPU power and I/O and net bandwidth.

If you talk about incoming messages - the main limiting factor are the
content scanners. For a customer we designed a mail system accepting
roughly peaks of 40 messages per second, including content scan, and
delivery to a Dovecot IMAP server..

Said this - missing performance you get by scaling, but missing
flexibility you cannot simply add by scaling.

Important points I forgot (I'm biased to Exim :)): its logging
capabilies, and Exim was designed with reliability in mind. I never lost
messages without any traces.

But - to be honest about scaling - there are some week points, Exim has,
if it comes to scaling. Currently we're limited to 15 Exim listener
instances using the same shared spool directory, and there are
other challenges with shared berkely DB files Exim uses as (non critical)
"hint" files.

    Best regards from Dresden/Germany
    Viele Grüße aus Dresden
    Heiko Schlittermann
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