On Thu, 21 Oct 1999, Tony Gale wrote:
> There's always an exception. For example, legacy systems with strange
> (but conformant) IP stacks - some VMS systems for example. I would
> love to be able to do set per-host concurrency for such systems where
> I know *exactly* what the upper limit on concurrent connections it
> can handle is, cause it's defined in it's IP / MTA implementation.
I am the person who started this thread. For those who are curious. We run
Qmail on our Listserv. We recently upgraded the system on which our
Listserv runs to a considerably faster machine. As a result when our
semester started and more and more students began to use our Listserv for
their courses, our Listserv started sending out hundreds of messages in
bursts to our primary Unix cluster that some 40,000 people use for their
e-mail access. At about this time, we added a lot of graphical e-mail
access via IMAP on our central via IMAP. This new IMAP traffic, combined
with our faster flow of Listserv traffic was bringing our main Unix system
to its knees at certain points during the day. Right now, our central Unix
system uses Sendmail as its MTA. We are giving serious consideration to
migrating it from Sendmail to Qmail since we have had such good luck with
Qmail on our Listserv and we also plan on doing some additional changes to
better process e-mail for our users.
At first, we wanted to set a low concurencyremote value just for our
central Unix system since its what most of our lists' subscribers use for
their e-mail. As it turns out, I think we were initially too generous with
the concurrencyremote setting anyway on our Listserv. It was set to a
value of 50 which we set quite a while ago, if I am not mistaken. I halved
that value a couple of days ago. As a result, our central Unix system is
no longer being bombarded with excessive Listserv traffic, but response
time via e-mail from our Listserv to our central system and others is
still acceptable.
As a result, we no longer need to do anything special to accommodate our
central e-mail system. Even so, the responses I saw on the Qmail list
provided an excellent learning experience for me and I appreciate everyone
who took the time to reply.
Thank you
