[Mimedefang] Multiplexor-queue problem

David F. Skoll dfs at roaringpenguin.com
Thu Jul 24 20:16:01 EDT 2003

On Fri, 25 Jul 2003, Mathew Thomas wrote:

> I restarted the sendmail+MD, but the multiplexor processes doesn't show "-q , -Q"  flags.
> #ps -ef | grep multiplexor
> defang  5345     1  0 08:53:34 ?        0:00   /usr/local/bin/mimedefang-multiplexor -p /var/mime/MIMEDefang/mimedefang-multip

"ps" truncates the output, which is why you don't see queueing.

> I loaded the gateway by sending 100 mail. The Gateway started 20 MD
> process and looks like queued two or three (from syslog), then I
> started to get "No free slaves" warning.  I got the following in the
> syslog:

This is the expected behaviour.  The purpose of queueing is to try to
allow SMTP transactions that have *already started* to run to completion.
If all slaves are busy, then *new* SMTP connections will be rejected.

> Also where does multiplexor queue the mail.

It doesn't queue the mail.  It just defers the request ("is this
sender OK" or "please scan this message") until a slave becomes
available.  The queueing mechanism is a very short-term queue based on
the theory that once you've started an SMTP transaction, you should
try hard to complete it rather than failing it partway through because
of a lack of slaves.  The idea is that once you've committed resources,
it's better to see things through than to give up partway, because then
the resources you've already spent are completely wasted.



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