[HowTo] Replace courier with dovecot

[simple]

After successfully switching to dovecot to speed up the imap access a few months back, I was pretty happy with the result. A few months later the mail access speed dropped rapidly to levels even slower than courier was before. Does dovecot have some known limits I didn't see? The mail folder is pretty big, some couple 100 folders and approx 100.000 mails all together (5gig space used).

The courier speed was always a little slow, but ok to work with, dovecot was pretty much faster to start with, and is way slower now

Someone came across this problem before? I could find no help/reference in google.

[aseques]

(09-19-2010 01:39 PM)simple Wrote:  After successfully switching to dovecot to speed up the imap access a few months back, I was pretty happy with the result. A few months later the mail access speed dropped rapidly to levels even slower than courier was before. Does dovecot have some known limits I didn't see? The mail folder is pretty big, some couple 100 folders and approx 100.000 mails all together (5gig space used).

The courier speed was always a little slow, but ok to work with, dovecot was pretty much faster to start with, and is way slower now

Someone came across this problem before? I could find no help/reference in google.

Nope, the most I saw in dovecot are about 2G and never heard of problems.
What version are you working with? What's the filesystem of your server? Are you using the howto configuration or something special?

[simple]

The server I tested dovecot on is plain simple ispCP 1.0.5 on Lenny, the only mod used is dovecot instead of courier (mostly after the howto here and some help from the official dovecot/courier howto). Filesystem is ext3, but the only slow application is dovecot (database / apache are pretty much fast as ever), so I ruled out the hard drive / filesystem as the main problem. Ram is ok, cpu usage pretty normal, no "standard" explanation why dovecot should break down like that.

If there's no easy fix I'll try to switch back to courier and test the speed with the "old one", just thought I'd ask first

Markus

[aseques]

(09-20-2010 11:08 PM)simple Wrote:  The server I tested dovecot on is plain simple ispCP 1.0.5 on Lenny, the only mod used is dovecot instead of courier (mostly after the howto here and some help from the official dovecot/courier howto). Filesystem is ext3, but the only slow application is dovecot (database / apache are pretty much fast as ever), so I ruled out the hard drive / filesystem as the main problem. Ram is ok, cpu usage pretty normal, no "standard" explanation why dovecot should break down like that.

If there's no easy fix I'll try to switch back to courier and test the speed with the "old one", just thought I'd ask first

Markus

It might be the amount of files of the directory.
ssh to the server and go to the home folder for that user. (/var/mail .../username/)
Once there type a ls and look how much it takes. Very often having 100000 files in a single directory degrades the performance when reading from there.
Maybe distributing the mail into separate folders would solve your problem in that case.

[fluser]

Hello Aseques

Do you know, if this mod is implemented in the Setup of IspCP 1.0.8?
What kind of problems will I have, when I upgrade from 1.0.7 to 1.0.8 with this mod?

Thanks and best Regards
Fluser

[aseques]

Currently there's ONLY one official installation with courier, I've been using dovecot since pre 1.0.0 version and I have been always able to update the system.
It's up to you, in my opinion, it really worths the effort...

[simple]

I can only speak about my experience with the problems mentioned above: with very heavy mail usage, dovecot is kind of slow - even compared to courier. The much simpler courier setup seems to be favorable with a truckload of mails. To the original question: Once switched to dovecot, upgrades should pose no problem.
Markus

[Sweil]

nice work & great how-to. thx a lot!

[Obi_Wan]

I've added the dovecot manager to trunk. Hopefully that will solve many problems

[Presssack]

(06-14-2011 01:59 AM)Obi_Wan Wrote:  I've added the dovecot manager to trunk. Hopefully that will solve many problems

Thanks!!!