Hey everyone,
I recently migrated a whole bunch of servers from qmail to exim (currently
4.60). Among these are an outbound mail submission agent (hereby called
a.msa) and an apache web server (hereby called b.www).
The exim.conf for both are here:
http://test.seattleserver.com/exim/exim.conf.msa - for a.msa
http://test.seattleserver.com/exim/exim.conf.standard - for b.www
b.www hosts websites for several clients. Among these is one who sends out a
mailing to a couple thousand people every day, using a commercial PHP-based
mailing list management program (*sigh*) called 1-2-all
(
http://www.activecampaign.com/12all/). With the (fairly standard) qmail
setup, everything ran quietly and fine. After switching to exim, when the
mails are sent out each midday, load on b.www rises above 5, and load on
a.msa rises above 16. These numbers are consistant from day to day.
What am I doing wrong? Or the more likely question - what is configured
insufficiently? I think that the concurrency limits are what made qmail run
nicely. I took a look at the rate limiting stuff added to 4.60 but am not
exactly sure where the best place to add it is, or whether it's the best
approach to this problem. Looking at the logs since I added the sender rate
reporting - b.www routes over 1600 messages in a 10 minute period.
The goal is to reduce load to a normal level while not actually stopping any
mail delivery - just slowing it down a bit. I do not think all of the (PHP
and the like) software on b.www can handle retrying if the mail server there
does not accept their mail on the first try, so exim on b.www must not return
a "server too busy" sort of response. a.msa in theory could, as long as it
does not do that to authenticated clients.
If I'm guessing correctly, the qmail approach seems the best in this situation
for the b.www exim server - accept mail as fast as it comes in, but then
limit the outgoing concurrency rate, though this may be better if the a.msa
exim server has rate limiting?
That may keep the load from spiking so much on a.msa, but the mystery
remains - why does the load go up at all on b.www? That makes no sense to
me.
Any advice on how to alter my configuration to deal with this problem in the
most elegant manner possible very welcome.
Cheers,
--
Casey Allen Shobe | cshobe@??? | 206-381-2800
SeattleServer.com, Inc. |
http://www.seattleserver.com
