[Mailman-Users] Slow Processing/Delivery

[Brad Knowles]

At 3:23 PM -0500 12/14/06, Jason Rotunno wrote:

>  We're experiencing some significant delays with our mailman lists. Some
>  messages are delivered instantly, while others can take hours (or over a
>  day) before it's delivered.

A certain amount of delay is not unusual, and variable amounts of 
delay for busy servers is not unusual.

What is unusual is the level of variable delay you're talking about.

>  We're running about 8-10 mailing lists, with membership numbers ranging
>  from a dozen members to about 1,000 (though there isn't much activity on
>  any of them), and our MTA is postfix. The delays aren't confined to one
>  list and they're not consistent. I don't believe there are mail delivery
>  delays with messages not sent to mailman.

There's some stuff in the FAQ on performance-tuning, but most of it 
has to do with things that are outside of Mailman itself.

>                                             Does mailman do any kind of
>  prioritizing depending on system load?

Nope.


Things you can do with Mailman include splitting large lists up into 
several smaller lists and then setting up a parent "umbrella" list to 
take over the function of the existing single list.  This helps 
performance internal to Mailman itself by reducing competition for 
locks on the Python database where all the list configuration and 
user subscription information is stored.

You can also create multiple sets of queue runners for each queue, 
and they will process the data in that queue in parallel.  However, 
this is a pretty advanced configuration for Mailman, and is not well 
documented.  What little documentation you will find on this subject 
is mostly contained within the source code and the Defaults.py file, 
as opposed to the FAQ Wizard.


Of course, you want to do all the other performance tuning things 
that are described in the FAQ, to make sure that as much of system 
performance as possible is made available to Mailman, and you don't 
have multiple processes fighting for limited resources.

-- 
Brad Knowles, <brad at shub-internet.org>

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