[Dovecot] performance problems with rc10 and solaris 10

[Jeff A. Earickson]

Hi,

I am running dovecot rc10 on a Sun E220R (sparc) for 3000 users with Solaris
10 version 6/06 plus current patches.  While the performance isn't great 
(it is a slow 2 cpu x 450 MHz box), it isn't bad either.

I use mbox format (/var/mail is NFS mounted) and ZFS for home directories.
Authentication is via PAM.  PAM uses kerberos to Active Directory.

I have the following in my /etc/system file for dovecot:

* double file descriptor limits for dovecot
set rlim_fd_cur = 65536
set rlim_fd_max = 131072

I also discovered that I need this setting in my dovecot.conf, or it
will fail over with the "shutting down too early/too many open files" 
problem that is often discussed on this list:

login_process_per_connection = no

Are you sure that your E450 isn't swapping?  The "growing data stack"
sounds like lack of memory/swap issues.

Jeff Earickson
Colby College

On Thu, 19 Oct 2006, Dominik Saar wrote:

> Date: Thu, 19 Oct 2006 14:04:03 +0200
> From: Dominik Saar <dominik.saar at 1und1.de>
> To: dovecot at dovecot.org
> Subject: [Dovecot] performance problems with rc10 and solaris 10
> 
> Hi,
>
> i have 2 dovecot imap server running on solaris 10
>
> The primary server with dovecot 1.0.alpha4 is running with best
> performance on Sun Sparc E4k5 with 8x 450MHz
>
> The secondary with rc10 has ugly performanceproblems on Sun E450 wth 4x
> 450MHz. Every new imap process takes permanent 25% cpu usage
>
> List the folder and fetch message are both slowy!
>
> Both servers are configred with ldap backend
>
>
> preventive i deleted for rc10 the complet index and controlfiles,
> because the spooldir is a sync from the masterserver with dovecot
> alpha4. I thought its a little bit slowy because of my 30.000 mails.
>
> the indexfiles are created now, but the still ugly slow ....
>
> For debugging i compiled rc10 again --with-debug=yes and start dovecot
> with solaris truss
>
> truss tells nothing to explain this behavor
> logentrys from dovecot has this warnings:
>
> -->
>
> dovecot: Oct 18 14:51:47 Warning: IMAP(saar): Growing pool 'storage'
> with: 1024
> dovecot: Oct 18 14:51:47 Info: IMAP(saar): dirsize quota limit =
> 750000kB
> dovecot: Oct 18 14:51:47 Warning: IMAP(saar): Growing data stack with:
> 32768
> dovecot: Oct 18 14:51:47 Warning: IMAP(saar): Growing data stack with:
> 65536
> dovecot: Oct 18 14:51:48 Warning: IMAP(saar): Growing data stack with:
> 131072
> dovecot: Oct 18 14:51:48 Warning: IMAP(saar): Growing pool 'uidlist
> record_pool' with: 32768
>
> <--
>
> also i compiled rc10 --with-notify=none, no result
>
> to ensure it isn´t the solaris system, i compiled alpha4.
> Result: good performance
>
> Any ideas?
>
> Cheers
>
> Dominik
>
>