[Mailman-Users] Email response very slow using Mailman and sendmail

Hank van Cleef vancleef at lostwells.net
Thu Apr 17 19:55:15 CEST 2008

The esteemed Patil, Manjiri S has said:
> Hi Hank and mark , 
(snipping for brevity)

> I do see that SENDAMAIL is trying to send messages only to bunch of
> people which varies from 10 to 50 at time. Also how do I tune up
> SENDMAIL with number of recipients to process at one time?
> ****Apr 17 09:30:30 smgpub sendmail[27208]: m3HD1x7v027207:
> to=<awolk at bu.edu>, delay=00:28:31, xdelay=00:28:31, mailer=esmtp 
> 9147447, relay=relay.bu.edu. [], dsn=5.1.1, stat=User
> unknown
> ****Apr 17 10:00:02 smgpub sendmail[27208]: m3HD1x7v027207:
> to=<... at bu.edu>,<.... at bu.edu>,<....da at bu.edu>,<.....@>
> ,<.... at bu.edu>,<.... at bu.edu [more], delay=00:58:03, xdelay=00:58:03,
> mailer=esmtp, pri=9147447, relay.bu.edu. [], dsn=2.0.0,
> stat=Sent (m3HD1x78004079 Message accepted for delivery)
> ****Apr 17 10:00:02 smgpub sendmail[27208]: m3HD1x7v027207:
> to=<rkgupta at bu.edu [more], delay=00:58:03, xdelay=00:58:03,
> mailer=esmtp, pri=
> 7, relay=relay.bu.edu. [], dsn=2.0.0, stat=Sent
> (m3HD1x78004079 Message accepted for delivery)

I've snipped out a lot of you post for brevity, but it does seem clear
from what you've provided that your issues are primarily sendmail
issues, not Mailman.  

I'll make the assumption that your listmember base is all, or almost
all, at bu.edu, and that it is primarily students (plus faculty).  

You did not show the log message showing the outgoing message from
listname-bounces (Mailman) that give the size and nrcpts.  This is
what is being sent by Mailman as MUA to sendmail as MTA.  Also, please
don't snip log messages when posting them.  

I see a couple of things you can probably change to get radical
improvement fairly quickly.

1. If your outgoing (from listname-bounces) log message shows
nrcpts=50, or some other big number, put a limit on what Mailman is
allowed to send.  In the $MMROOT/mailman/Mailman/mm_cfg.py file, put
in (or modify an existing) line to read:


Then restart the Mailman Qrunner daemons.  

Reason:  sendmail will terminate sending of multiple recipient mails
on the first failure.  The remaining messages are deferred for retry.
Your user base is probably high-turnover (students entering and
leaving), so a lot of your delays are "peeling the onion" retries.

2. It appears that your sendmail outgoing daemon is being started with
a retry time of 1 hour.  Do a ps -ef |grep sendmail and look for lines
that read

 /usr/lib/sendmail -bd -q1h

The -q argument is the retry interval.  Find where sendmail is being
started and arrange to restart it with -q15m (15 minutes).  

Sendmail is generally started by a boot-time rc file, so you'll need
to find that file on your system (Solaris 9 is /etc/init.d/sendmail)
and adjust the startup appropriately.  

Reason:  Four retries per hour vs. 1 per hour should be obvious. Don't
cut the time down so much that sendmail retries while still processing
messages from the last retries.  

3.  Use the mailq utility to watch queue processing.  

4.  Any bounces with a DSN of 5.x.x should be going back to Mailman
and shown in the $MMROOT/mailman/logs/bounce log.  Check that you are
getting them.  Beyond that, you can set your Mailman bounce processing
from the Mailman List Administration screens.  I run with 3.0 (three
consecutive days), and 3 7-day notification intervals.  If you need to
clean up your listmember data base because of account turnover, I'd
suggest cutting that down to 2.0 bounces and 2 4-day notifications or
something similar.  

You should familiarize yourself with sendmail, and generally be on top
of any peculiar characteristics of your user base and the sites you
deliver mail to.  You should have the O'Reilly "Sendmail" (the "bat
book") and the O'Reilly sendmail 8.13 supplement.  Also, the Usenet
news group comp.mail.sendmail, the sendmail README (in the
distribution), and the sendmail web site, which has a huge (and
valuable) FAQ.

In general, the Mailman developers don't work with sendmail on a daily
basis.  I'm jumping in here as a Mailman user site manager who is
currently working delivery problems to yahoo.com listmembers, so I am
using the same resources you need to use to tune your system.  


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