On Mon, 20 Nov 2006, Timo Sirainen wrote:
Date: Mon, 20 Nov 2006 18:36:17 +0200 From: Timo Sirainen tss@iki.fi Reply-To: Dovecot Mailing List dovecot@dovecot.org To: Jeff A. Earickson jaearick@colby.edu Cc: dovecot@dovecot.org Subject: Re: [Dovecot] rc14 and rc15 performance issues
On Mon, 2006-11-20 at 09:25 -0500, Jeff A. Earickson wrote:
Hi,
I am stuck at rc13 because rc14 and rc15 have both failed to keep up with imap connections on my (slow old) system. I have the problem where if a lot of people check their email at once (like at the top of the hour) then my load goes way up and things slow to a crawl. My setup: Solaris 10 on an E220R, mbox format, imap and imaps only. I also use "login_process_per_connection = no". Any suggestions?
Like Marcus asked, is it I/O load or CPU load? And if CPU, what process is using it? What passdb and userdb do you use? If you're not sure if it's imap process or something else doing it, you could eg. run with rc15's imap and everything else with rc13, or vice versa.
Anyway I don't see what could have caused anything to work slower..
Because of screaming users, I didn't have a lot of time at analyze the situation. The cpu load climbed and climbed, to 40+ (uptime number), memory was really low, it may have been paging. passdb is passwd-file and userdb is passwd, nothing exotic here.
We have times like the top of the hour, and 11 AM especially, where everybody checks their email at once. This tends to spike the load. With rc13, it drops back quickly. With rc14/15 it goes up and stays there. Memory leak someplace?
Our IMAP server is seriously underpowered and needs to be replaced.
Jeff Earickson Colby College