Forum OpenACS Q&A: exim vs qmail for MTA

Posted by Stan Kaufman on 03/01/02 09:01 PM

Looking through the OpenACS archives, it appears that many/most here
use qmail for your MTA. One compelling reason is the way qmail threads
outgoing mail into separate processes (discussed here:
http://openacs.org/bboard/q-and-a-fetch-msg.tcl?msg_id=0001DG&topic_id=11&topic=OpenACS)

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
over exim?

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!

2: Response to exim vs qmail for MTA (response to 1)

Posted by Jonathan Ellis on 03/01/02 09:15 PM

if exim ain't broke don't fix it. (I use postfix, and I'm quite happy with it.)

3: Response to exim vs qmail for MTA (response to 1)

Posted by Mike Sisk on 03/02/02 03:44 PM

Here are several benchmarks comparing MTAs:

http://www-dt.e-technik.uni-dortmund.de/~ma/postfix/
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.

4: Response to exim vs qmail for MTA (response to 1)

Posted by Don Baccus on 03/02/02 03:56 PM

"* The per-mail overhead is significant, multi-RCPT is always superiour performance-wise to single-RCPT."

The bboard e-mail performance would be boosted considerably if it sent bulk mail rather than ns_sendmail every person individually ...

5: Response to exim vs qmail for MTA (response to 1)

Posted by Mat Kovach on 03/02/02 04:40 PM

MTA, as I see it, are a matter of taste for the most part. For most MTA fucntions each handles thems. Performance, configuration, etc. all seem to even out is some why.

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)
easily.

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.

6: Response to exim vs qmail for MTA (response to 1)

Posted by Jon Griffin on 03/04/02 02:38 AM

The main reason to use qmail is security. Lookup qmail and find how many exploits there have been.... zero, thats what I thought.

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.

7: Response to exim vs qmail for MTA (response to 1)

Posted by Mike Sisk on 03/04/02 04:37 PM

For an alternate POV on qmail and the cult of djb check out http:// www.linuxmafia.com/~rick/faq/#djb.

Of course, djb thinks the above author is an idiot.

8: Response to exim vs qmail for MTA (response to 1)

Posted by Andrew Piskorski on 05/21/02 07:25 PM

That Rick guy is an idiot. Or at least, I've never heard of him before, but he sure comes across like one on that web page. E.g., he spouts that qmail is "characterised by bizarrely wrong design" because DJB insists that qmail "binary packages must install all files including libraries, binaries, and configuration files within /var/qmail". Except, that has nothing to do with the design of qmail at all... I've never looked at the qmail code myself, maybe it really is poorly designed - but that Rick's guys statement has pretty much zero relevance to answering the question of whether it is or not. Very poorly reasoned.

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.

9: Response to exim vs qmail for MTA (response to 1)

Posted by Andrew Piskorski on 05/21/02 07:44 PM

Btw, Rick Moen does have plenty of usefull or interesting info on his website, much of it written by him, and well written at that. So he's clearly not really an idiot. :)