[Mailman-Users] Mailman 2.1.6 slowness...?

Brad Knowles brad at stop.mail-abuse.org
Sat Jul 16 14:27:43 CEST 2005

At 8:15 AM -0400 2005-07-16, Jeff Squyres wrote:

>  Clarifying question, however -- will mailman only make one SMTP
>  connection at a time (and block all further outgoing processing until
>  that one SMTP connection is complete)?


>                                          Is this why you're suggesting
>  proper tuning of SMTP_MAX_RCPTS?


>  We didn't change the value of SMTP_MAX_RCPTS between 2.1.5 and 2.1.6
>  (500).  Perhaps this is too high (none of our lists have close to 500
>  subscribers in a single domain).

	That's not done on a per-domain basis.  Let's say you have 1000 
subscribers.  With SMTP_MAX_RCPTS set to 500, then you will send out 
one copy of the message to the first 500 recipients, wait for it to 
be fully accepted by the MTA, and then send out the second copy of 
the message to 500 recipients.  The result can extremely "peaky" in 
nature, kind of like taking a car and shifting the gear box directly 
from 5th gear to 1st, and then from 1st back to 5th.

	If you break that up into smaller chunks, the system can be 
processing more of those chunks in parallel, and each chunk can be 
accepted faster.

>                                    We routinely see large sendmail
>  outgoing queues (and did with 2.1.5, too).

	Given your configuration, I'm not at all surprised.

>  A comment in one of the prior e-mails made me go check the other qfiles
>  directories -- we have a few hundred files in the qfiles/bad directory
>  (~200) and a few thousand in qfiles/shunt (~4000).  What are these
>  files? (pardon the newbie question)

	The stuff in the "shunt" queue are messages that were malformed 
in some way, and Mailman shoved them off to the side because it 
couldn't deal with them.  Whenever you stop and restart Mailman, it 
will go through the "shunt" queue to see if there is anything it can 
handle now that previously it could not.  This can really hurt 
startup times, and a large "shunt" queue can hurt you any time you 
have to move messages into it.

	You might want to consider turning off Mailman, moving most of 
the "shunt" messages to a different directory name (maybe shunt.old, 
or shunt.2005-07-16, or whatever), and then creating a new shunt 
queue with the exact same ownership and permissions.

>  Thanks for all your suggestions -- we're checking them in the
>  background, but it takes a little time to check properly.  Also, based
>  on your replies, I think we need to triple check with our sendmail
>  maintainers and ensure that they really, really didn't change anything
>  between when we were running 2.1.5 and 2.1.6 (they swear that they
>  didn't, but we'll ask again).

	You definitely want to learn more about your sendmail configuration, yes.

Brad Knowles, <brad at stop.mail-abuse.org>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

     -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
     Assembly to the Governor, November 11, 1755

   SAGE member since 1995.  See <http://www.sage.org/> for more info.

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