[Dovecot] Stale imap processes

Fran Fabrizio fran at cis.uab.edu
Thu Aug 3 23:58:58 EEST 2006

Ok, my head is swimming after catching up, but I think this is what I've 

I am using Fedora Core 5 and dovecot RPMs.  The RPM that shipped with 
FC5 was:


after observing the stale imap processed I upgraded this to:


Both of these are built with ioloop=poll.

I am still seeing the stale processes with beta8.  Sounds like I need to 
build from source using ioloop=kqueue to maybe clear up this issue.  Did 
I interpret this correctly?  And should I stick with beta8 or move to rc2?


Renaud Allard wrote:
>>> Unfortunately, I had the problem on OpenBSD with dovecot 1.0rc2. Stale
>>> imap processes when _NOT_ using kqueue (using poll). Using kqueue solved
>>> the problem. Not sure if it's the same on FreeBSD, but it seems that
>>> using kqueue solves the stale processes problem both on OpenBSD and
>>> NetBSD. On linux, kqueue doesn't produce stale imap processes either.
>> I have had a number of reports that kqueue, specifically kqueue for
>> the file change mechanism (--with-notify=kqueue), causes the hanging
>> and disabling this allowed regular operation. kqueue for the I/O loop
>> mechanism causes dovecot processes to crash under certain (unknown)
>> conditions. If poll is causing problems then there are definitely some
>> nasty bugs lurking in the code base. The problem with the file change
>> mechanism and kqueue popped up somewhere between beta8 and rc2.
> I use --with-ioloop=kqueue
> I had no problems with beta8, and noticed stale imap processes after
> upgrading to rc2. Someone suggested using --with-ioloop=kqueue and this
> indeed solved my problem.
> Note that while I have no more imap processes hanging, I noticed that
> sometimes thunderbird complains about being unable to copy mails in sent
> folder. This wasn't the case in beta8.

Fran Fabrizio
Senior Systems Analyst
Department of Computer and Information Sciences
University of Alabama at Birmingham

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