Robin Helgelin writes:
We?re using dovecot 1.0.7, which seems to be the latest version available on CentOS 5.
It wouldn't be a bad idea to update this if you can, even if you have to compile it yourself. You'll benefit from many bug fixes, one of which may solve your problem.
Downloading emails are dead slow. Really small emails goes quickly, but normal emails and emails with attachments are so slow to download it?s almost ridiculous. I?ve googled some and found that it could be related to quota, but I disabled the quota plugins on imap with no difference.
The problem with "slowness" is that it can result from just about anything. I've seen reports of slowness caused by LDAP handups, filesystem and I/O polling, client issues, network issues, firewall issues, anti-virus stuff, resource starvation. That's just the stuff I remember.
You'll need to dig further to reduce the scope of where it can be going wrong. I would suggest getting hints from
- process tracing
- network snooping
- logsTest if it's a mail client issue by sampling more than one mail client (or better yet, talk IMAP directly to the server via telnet or netcat and download a large piece of Email).
If that provokes a problem, work your way back to the server and do the same thing on the server itself (bypassing the network stack) and see if the problem still persists.
Depending on what you find out, at least you'll know which side of the fence you should be looking at.
(Also, asks yourself the obvious question: did you change anything before dovecot performance went down the tubes? New hardware? Patches?)
Joseph Tam <jtam.home@gmail.com>