Viktor Dukhovni:
> On Mon, Oct 10, 2022 at 10:27:37AM +0200, juan smitt wrote:
>
> > How can one directly monitor the effectiveness of the increased number
> > of Postfix SMTP server processes?
> > (https://www.postfix.org/STRESS_README.html)
> >
> > Is it true that this scales up dynamically until the limit,
>
> Yes, a new smtpd(8) process is started on demand, if a new connection
> comes in while all extant processes are busy. Once started, each
> process handles up to $max_use connections, exiting after that, or
> when idle for at least $max_idle.
>
> > which means I can monitor it indirectly by counting the number of
> > processes (and also checking the delay in the mail log)?
>
> The delay times in the mail log are not a direct indication of either
> too many or too few smtpd(8) processes.
When Postfix logs "delays=a/b/c/d", the field 'a' is measured from
the time that Postfix creates the queue file (typically after the
first valid RCPT TO command). It does not contain information about
the delay that the client may have experienced before the Postfix
SMTP server sent its initial greeting, time spent in reverse/forward
lookups of the client name and IP address, etc.
Wietse
