[Dovecot] IMAP timeout problem

[Ken A]

Vasantha Narayan wrote:
> Hello,
> 
> We are running dovecot 1.1.2 on a Solaris 10 box.  We have been
> running the same configuration for about a year without a problem.
> We have a different cert for POP and IMAP.
> 
> Recently we made two changes.  The cert for IMAP expired and we had
> to install a new one.  We applied some patches to the SAN disks that
> hosts the mail partition.  These changes were made over a weekend and
> the system was rebooted. 


Do you have any baseline benchmarks for your SAN?
What does vmstat 2 or iostat -c 2 say about i/o wait?

Ken

  There were no errors in the logs and
> everything worked fine until the following Monday morning when IMAP
> connections increased.   When IMAP ports started getting hammered in
> the morning, IMAP clients started getting "IMAP time out" errors.
> When this error occurs, IMAP freezes and IMAP clients such as,
> Thunderbird and Squirrelmail  are not able to connect to the IMAP
> server (both IMAP and IMAPS).   We cannot get a telnet connection to
> the IMAP port or a openssl connection to the IMAPS port.  Kill -HUP
> of the dovecot server solves the problem.  But again, when the usage
> increases, the problem surfaces again.  There is no problem with POP
> or POPS.  It continues to function normally while IMAP times out and
> freezes two or three times a day.
> 
> Any clue where the problem might be?  The debug log does not have any
> useful pointers.
> 
> Thanks.
> 
> Vasantha
> 
> 


-- 
Ken Anderson
Pacific Internet - http://www.pacific.net