number of imapd processes never decrease

Vladislav Kurz vladislav.kurz at
Thu Sep 17 09:23:35 EDT 2015

On Thursday 17 of September 2015 Niels Dettenbach <nd at> wrote:

> Am Donnerstag, 17. September 2015, 14:19:42 schrieb Sebastian Hagedorn:
> > > Cyrus is running an a recently updated Ubuntu 14.04. lts server. Is
> > > there anything I can do?
> > 
> > we are still on 2.4.x, but we had a similar problem that we resolved this
> > 
> > way:
> >   imap          cmd="imapd -U 10" listen=""  ...
> ...interesting to see that this happens on other Ubuntu systems as well - i
> saw this on some Ubuntu systems (only on Ubuntu setups) in the past too,
> without havin the option to dig in deeper what's happen there.
> If someone has further investigation results or experiences about this,
> this would be interesting...

I have set "imapd -U 30", maxchild=400, and I see gradual grow up of process 
numbers. Some instances are very long lived, (almost 3 months). In 
/var/lib/cyrus/procs I can see that some users have about a dozen of 
connections to the same mailbox/folder (trash is a favorite). And also quite a 
lot connections with no user associated. Thus from time to time (when I get 
above 350 processes), I kill imapd processes with no user, or with duplicates 
(same IP, same user). I just feel as if the -U option does not work well.

Just to note, the number of processes is decreasing during night, but the max 
and min values grow each day. I have a graph if someone is interested.

Best Regards
        Vladislav Kurz

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