[Mimedefang] Process limits and loads

[David F. Skoll]

On Wed, 30 Apr 2003 listuser at numbnuts.net wrote:

> Now I know these are temp errors and that delivery will be attempted many
> more times.  It's about a 50/50 split between errors for Sendmail and
> errors for sm-msp-queue.  I believe the problem is that I have more
> Sendmail processes than MIMEDefang processes.

That's OK, because a given MIMEDefang process isn't kept busy for the
whole duration of an SMTP transaction.  The MIMEDefang slaves are used
in short bursts after MAIL FROM:, RCPT TO: and the end of DATA.

> define(`confMAX_DAEMON_CHILDREN',`60')

I would not limit MAX_DAEMON_CHILDREN at all.  It opens you up to a
DoS attack -- someone just needs to open 60 SMTP connections to your
machine and then do nothing.

It's better to let the OS limit the children naturally by running out
of resources.

> I just increased MX_MAXIMUM to 15 from 10 this morning.  Checking the logs
> I see that it has actually helped.

That's good.  With 1GB of RAM, my rule of thumb of 16MB/slave says you
can make MX_MAXIMUM as high as 64.  I would do that, and then keep
an eye on the highest number of slaves that actually get used.

--
David.