On 6.3.2013, at 14.44, Angel L. Mateo amateo@um.es wrote:
While monitoring my servers' behaviour (ubuntu 12.04 with dovecot2.1.9, with about 70000 users) I have found that lots of disk usage is done by dovecot process (the parent process). Since lmtp, imap and pop3 connections are handle by their own process, what could be the reason of this?
In any case, I don't understand why dovecot parent process has these huge amount of IO, since, I guess, IO should be done by user's processes (lmtp, imap or pop), not dovecot parent.
Right.
My only hypothesis is related with log messages, but then IO should be done by rsyslog process, not dovecot, shouldn't it?
Master process doesn't even log messages, log process does that.
There is no reason why dovecot master process would be doing any disk IO. Maybe whatever you're looking at is counting the child processes' disk IO as well?