Author: Ian FREISLICH Date: To: Nigel Wade CC: Exim users list Subject: Re: [exim] Per-User SpamAssassin config
Nigel Wade wrote: > Richard Hobbs wrote:
> > - Once exim heavy is running (and exiscan is therefore enabled) I need to
> > setup the ACL stuff to allow exim to run spamassassin, but only if the
> > user's preferences exist.
>
> The problem with running per-user spam checking in an ACL is that you need
> to restrict messages to single recipients. This is wasteful of bandwidth
> both for you and the sending MTA when messages are originally sent with
> multiple recipients - the message has to be resent for each recipient. This
> applies to all messages, whether any of the recipients want spam checking or
> not.
The other problem is that per-user scanning is also wasteful of
system resources. At work before I migrated them to exim (from
qmail), we had 5 spamd servers serving about 90 mail servers. The
spamd servers had a 15 minute load average above 15 for most of the
day and scan times were in excess of 40 seconds. Since the move
to exim, Those 5 spamd servers are serving about 130 (growth in the
mean time) mail servers and their load hardly ever goes over 1.
