[Dovecot] Very High Load on Dovecot 2 and Errors in mail.err.

Timo Sirainen tss at iki.fi
Tue Jun 12 00:57:21 EEST 2012

On 12.6.2012, at 0.37, Jesper Dahl Nyerup wrote:

>> Yeah. Looks like a kernel bug. You could try if it goes away by disabling inotify in Dovecot. Either recompile with "configure --with-notify=none" or maybe you can disable inotify globally with:
>> echo 0 > /proc/sys/fs/inotify/max_user_watches
>> echo 0 > /proc/sys/fs/inotify/max_user_instances
> I can confirm that this removes the symptoms, and that it doesn't affect
> the service. Obviously IDLEing users are now only notified upon polling
> of the file system, but the I/O overhead of doing this seems minimal.

It actually doesn't increase I/O overhead at all. Dovecot always does polling, even with inotify, since inotify doesn't necessarily work with shared filesystems (e.g. NFS). The main difference is that users don't get immediate notifications of new mails now, but have to wait for mailbox_idle_check_interval.

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