On Wed, 14 Feb 2007, Marc Haber wrote:
> >The delivery process forks more than one subprocess. See section 1.13 in
> >the manual ("Delivery in detail").
>
> I see. IMO, the default is way too low, makes exim look bad when
> compared with postfix.
There is no sensible default that will suit all installations and all
requirements. The current default of 2 was set a long time ago -
changing it would affect existing sites when they upgrade. It is
perfectly reasonable for the vast majority of personal email, where
messages rarely have more than 2 recipients.
Sites that are doing predominantly mailing-list deliveries (with lots of
recipients per message) have normally got to look carefully at their
configurations in any case.
A thought: I wonder, from your previous mention of queue runners, if you
think that the queue runner is the *only* way messages are delivered? If
so, you haven't quite understood the way Exim (as normally configured)
works. If 20 messages arrive at once, all 20 will immediately be
delivered, using up to 40 simultaneous outgoing connections (with
remote_max_parallel at the default of 2). The queue runners work only on
messages that have previously had a temporary delivery error.
I said "as normally configured", because it is possible to make Exim
behave otherwise. If you set queue_only=true, then messages do indeed
sit on the queue and are delivered one at a time by a queue runner
(though you can have multiple queue runners).
--
Philip Hazel University of Cambridge Computing Service
Get the Exim 4 book: http://www.uit.co.uk/exim-book
