[Mailman-Developers] VERPing: ouch!

[Brad Knowles]

At 11:08 AM +0200 2004-07-13, Fil wrote:

>  Here's the smtp log line:
>  Jul 13 02:05:22 2004 (435) <20040712150834.DCA153680BD at alan.rezo.net> smtp
>         for 152991 recips, completed in 31782.241 seconds

	How does this compare to a normal, non-VERPed delivery for this list?

	I ask because Chuq Von Rospach has done some calculations on what 
should theoretically happen to your performance if you enable VERP, 
but I don't know of anyone who has actually timed the performance 
difference on large lists.

>  In any case, 2 seconds per VERP message for such a big list is too costly,
>  so I'll just disable VERPing the normal messages for now - with the price of
>  not being able to clean the list as efficiently as I could with the
>  occasional VERP.
>
>  I hope this feedback can be useful, if you have scalability in mind for MM3.

	This is really more of an MTA limitation, although there might be 
some things we can do to try to work around it with Mailman.  For 
example, it might be faster/lower overall load on the server if we 
had the MTA do the VERPing for us -- we're pretty sure that's 
supported by some MTAs (e.g., at least some versions of Exim), and we 
know it's faster for at least some of them (e.g., Exim).

-- 
Brad Knowles, <brad.knowles at skynet.be>

"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.