Forum OpenACS Q&A: exim vs qmail for MTA
use qmail for your MTA. One compelling reason is the way qmail threads
outgoing mail into separate processes (discussed here:
On the other hand, exim is the default MTA for Debian, and I know
there are a number of folks running Debian. How many of you have
replaced exim with qmail? Why?
Re the slow email processing in /bboard that Ben cites above, wouldn't
a work-around that queues up bboard notifications as the
/groups/group/spam* code does work just as well? Or does qmail have
some architectural advantages that deliver better speed/reliability
I'm configuring a new woody box (for a heavily-modified 3.2.5 OpenACS
install) and am trying to decide whether to stick with exim (which has
worked fine so far) or switch to qmail.
TIA for your opinions!
Here are several benchmarks comparing MTAs:
http://www-dt.e-technik.uni-dortmund.de/~ma/postfix/ a> http://www-dt.e-technik.uni-dortmund.de/ ~ma/postfix/bench2.html
According to these, Sendmail is faster than qmail, exim faster still, but Postfix is faster than any of them.
It should be noted the authors of the above benchmarks partake of Postfix-flavored Kool-Aid---YMMV.
The bboard e-mail performance would be boosted considerably if it sent bulk mail rather than ns_sendmail every person individually ...
Unlike your family, you generally get to choose your MTA :)
With that said, for bulk mailings and such qmail has the advantage of using VERP (http://www.jp.qmail.org/qmaildoc/RFC/RFCVERP.html)
I've found qmail's overall performace to be better (and email is a large part of what I do to pay the bills). Heck, what do you think most spammer's use? qmail.
But you could use any MTA and tune it to work with the bboard notifications. If your MTA is working for you, why switch.
(OpenACS) 3.x had the bulkmail modules (or at least talked about it) to handle unsubscribe requests. It might be helpful to had some bounce code handling to it so emails that are bouncing get their notifications blocked after x bounces (or x days). If you tune it further you could say and if one discussion is getting a large amount of bounces that you disable alerts for that dicussion also. That might help in reducing messages that are not be delivered and enlarging the queue.
Of course once you start to tune your mail sending/receiving/bounce procedures you'll start to lock yourself into a single MTA.
That being said, DJB hasn't done squat to it for several years and some new concepts have been added on by 3rd parties or not added at all. See courier-mta.org for some reasons.
Also, Maildir is the ONLY mailbox format you should use.
Varshavchik's Courier MTA complaints about qmail, that Jon pointed out above, make a lot more sense.
FYI, Debian users may want to grab Gerrit Pape's qmail, daemontools, djbdns, etc. packages. Unfortunately his documentation and discussion is so terse as to make unix man pages seem encyclopedic, but his packages seem to install fine, and the very limited use I've put them to so far hasn't turned up any problems.