Basically, we are fighting that for some time already. I've set up sendmail
to delivermode=q and it helped a little, since sendmail is not forking tons
of lmtpds this way. Could you tell me what is the glibc version you have?
btw, I've tried latest cyrus from cvs -- didn't really help.
Nick Ustinov
[EMAIL PROTECTED]
http://www.videinfra.com
-----Original Message-----
From: Krzysztof Sierota [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, April 18, 2001 11:44 PM
To: Dori Seliskar; Nick Ustinov
Cc: '[EMAIL PROTECTED]'
Subject: Re: forking problem
I'd like to confirm, that while evaluating the cyrus 2.0.12 server for
deployment of large intranet system, we have spotted exactly the same
behaviour.
When we started pumping messages into the server, it wouldn't show the pop3
prompt for 50 seconds. I'd like to ask if anyone of you have coped with the
problem we all are seing. We have been seing this behaviour on both our test
platforms that is redhat 6.2 2.2.14 kernel and redhat 7 with 2.4 kernels.
this is first time we are trying cyrus imap server, and this is a little
dissapointing..
thank you.
On Thursday 12 April 2001 16:57, Dori Seliskar wrote:
> Nick Ustinov wrote:
> > Hi!
> >
> > I use cyrus 2.0.12 + pam_mysql, sendmail 8.11.0 on a dual p3/550 with 1G
> > ram (linux redhat7, kernel 2.4.2).
> > I've faced a very strange problem -- when the system is under heavy load
> > (however, there is ~300Mb of free memory and free ~50% cpu) master
> > process is not forking new processes or doing it in a very strange way.
> > If i telnet to port 143 it just opens the connection but no cyrus'
> > prompt... it might delay for 40-50 seconds. Meanwhile sendmail tries to
> > deliver local mail and opens many connections to localhost that eat
> > memory, cpu, swap and then my box dies. If I kill sendmail when there
are
> > 900 of them and then start it again after 5-10 minutes it's ok... So i
> > suppose there are very many simultanous requests to master which it
can't
> > handle.
> >
> > Has anyone experienced something similar? Maybe it's a Linux problem,
but
> > I have no clue what to do.
> >
> > Nick Ustinov
> >
> > [EMAIL PROTECTED]
> > http://www.videinfra.com
>
> Nick,
>
> just to confirm, we are seeing exactly the same with cyrus 2.0.9 &
> pam_ldap. We also tried 2.2 and 2.4 kernels but the problem doesn't go
> away. We have about
> 70 k users and at rush hours cyrus slows down, there are many sendmail
> processes
> in "localhost user open" state and restarting cyrus & sendmail temporary
> solves the problem.
> There is no problem when there is only few concurent connections to cyrus.
> We are struggling
> with this problem quite for some time. Just for a tiny lead that we plan
to
> investigate - there
> was a discussion on linux-kernel list about some big delays on /dev/random
> in some cases
>
> http://boudicca.tux.org/hypermail/linux-kernel/2001week15/0064.html
>
> Maybe somebody more familiar with cyrus internals could tell more about
> this.
>
> BTW. When this happens load is not high ( 2-3 ) only cyrus is completely
> stuck.
>
> Regards,
>
> Dori Seliskar
