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

[Timo Sirainen]

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.

> virtual users are in mysql database and mysqld is running on another server (this server is ok).
> 
> Do I need better CPU or is there something going on that I do not understand?

Your CPU usage should probably be closer to 0%.

> login_process_size: 128
> login_processes_count: 10
> login_max_processes_count: 2048

Switching to http://wiki2.dovecot.org/LoginProcess#High-performance_mode may be helpful.

> mail_nfs_storage: yes

Do you have more than one Dovecot server? This setting doesn't anyway work reliably. If you've only one server accessing mails, you can set this to "no".