[Dovecot] What is normal CPU usage of dovecot imap?

[Timo Sirainen]

On 3.1.2012, at 17.38, Mikko Lampikoski wrote:

> On 3.1.2012, at 17.12, Timo Sirainen wrote:
> 
>> On 3.1.2012, at 16.54, Mikko Lampikoski wrote:
>> 
>>> I got Dual Core Intel Xeon CPU 3.00GHz, over 1000 mailbox and almost 1 dovecot login / second (peak time).
>>> Server stats says that load is continually over 2 and cpu usage is 60%. top says that imap is making this load.
>> 
>> You mean an actual "imap" process? Or more than one imap processes? Or something else, e.g. "imap-login" process? If there's one long running IMAP process eating CPU, it might have simply gone to an infinite loop, and upgrading could help.
> 
> It is "imap" process and process takes cpu like 10-30 seconds and then PID changes to another imap process (process also takes 10% of memory = 150MB).
> Restarting dovecot does not help.

Is the IMAP process always for the same user (or the same few users)? verbose_proctitle=yes shows the username in ps output.

> If someone have lots of mails in mailbox can it make effect like this?

Possibly. maildir_very_dirty_syncs=yes is helpful with huge maildirs (I don't remember if it exists in v1.1 yet).