[Dovecot] Performance question

[Timo Sirainen]

On 19.7.2007, at 18.23, Stewart Dean wrote:

> I now have Dovecot in production and things are apparently trouble- 
> free. The one known problem is that initial client inbox load can  
> take 30 seconds - 2 minutes.  For instance:
> 'I got fed up waiting and went and got coffee'...this with a 3MB  
> mbox inbox...and my mail server is a substantial machine consuming  
> 25% CPU just for this person's IMAP session.

That sounds too much. Dovecot should take about the same time as UW- 
IMAP when initially opening the mailboxes.

> 1) Any tuning I can do to improve this?

http://wiki.dovecot.org/PerformanceTuning has some suggestions.

> 2) Any metrics, troubleshooting I should be doing to better  
> characterize the problem?

Can you easily reproduce this with any mbox file that's a few  
megabytes large? Does deleting Dovecot's indexes and immediately  
reopening the mailbox take as long? So does disk I/O have anything to  
do with the wait, or is it just CPU?

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