[Mailman-Developers] problem with VERP stuffing all the messages in one connection

[Marc MERLIN]

On Thu, Feb 28, 2002 at 07:56:03PM -0500, Barry A. Warsaw wrote:
> 
> >>>>> "MM" == Marc MERLIN <marc_news@vasoftware.com> writes:
> 
>     MM> When VERP is enabled, mailman apparently sends all the Emails
>     MM> over one SMTP connection.
> 
> Actually, I don't think it has anything to do with VERP.  Won't normal
> delivery do the same thing?  (I'm assuming you're not doing threaded

Nope, there are two things:
1) how many receipients in one Email (i.e. how many rcpt tos you sent per
   mail from). That's already an option in mailman
2) how many mail from/rcpt to/data you shove through one SMTP connection.
   That hasn't been an option so far, but since most configs are set to send
   at least 10 to 100 RCPT TOs per MAIL FROM, you typically end up sending
   less than 100 DATAs (at least that's apparently been my case so far).

With VERP, I'm now hitting #2. A 500 user list generates a huge SMTP
connection with 500 mail from/rcpt to/data.
For exim, the default for  smtp_accept_queue_per_connection is 10 (100 on my
server), so after 10  batches in one connection (10 users  with VERP or 1000
users with  normal delivery and a  batch size of 100),  exim spools messages
and leaves them to  be picked up by the next qrunner, which  may be run 15mn
later.

I'll definitely contribute exim documentation on how to tune the exim side
(along with the updated directors and the exim 4 version of the directors),
but I think we'd also kind of need:

> It probably ought to be something like
> SMTP_MAX_SESSIONS_PER_CONNECTION.

Yep.

Marc
-- 
Microsoft is to operating systems & security ....
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