Simone Caruso:
> On 06/04/2013 15:01, Wietse Venema wrote
> > There must be other solutions that can work with a fixed memory
> > budget and that can push excessive mail to a "low-priority" queue
> > that is processed when it does not interfere with other delivery.
> >
> > Any solution that requires knowledge of THE COMPLETE MAIL QUEUE
> > will be firmly rejected. I will not allow a built-in limitation on
> > the amount of mail that Postfix can handle.
> >
> (if i understood correctly the needs of Giorgio)
> Can be the following points the way to obtain round-robin delivery based on
> sender address/ip?
>
> 1. change the "incoming queue" directory structure indexing sub-directories
> with
> a per-sender index
> 2. changing the algorithm used by qmgr to move email from "Incoming" to
> "Active"
> queue, (a foreach over subdirs)
>
> This increases disks i/o but you can obtain a pretty fair delivery
> between senders
I just simulated the performance hit of 256 incoming queues by setting
hash_queue_names = incoming
hash_queue_depth = 2
and running smtp-source, sending mail to an alias for /dev/null.
Postfix queue performance for small messages already dropped by
30%, with the write cache enabled on a 10,000RPM SAS disk (which
is recommended for a production server only when the write cache
has a battery to survive power failures).
The performance drop will be worse with one queue directory per
customer, unless you have very few customers of course.
Wietse
