At 9PM +0000 on 12/02/13 you (Jason Lock) wrote:
Mail Issues - FreeBSD
Hello, my apologies if this may be the wrong forum but hoping that maybe someone might be able to provide some insight.
This may turn out to be something better addressed on freebsd-stable, but this is a perfectly good place to start.
Have a very sporadic and strange issue with our mail servers running Dovecot on FreeBSD. There are three servers hosting Dovecot with FreeBSD as the underlying operating system. All three connect to a NAS server, again running FreeBSD and ZFS.
Over NFS, I assume? What version, what mount options, and what type of authentication? What locking strategies is Dovecot using? Are there any suspicious messages in syslog on either machine?
When the specific issue occurs, clients connecting to check mail via POP3 or IMAP experience long delays and timeouts. To the point where POP3 Logins fail due to the timeouts. The issue is further compounded by clients increasing the number of attempts to check mail.
Are the delays happening before or after login?
If you can provoke this and get a 'procstat -k' for the relevant dovecot process this might be helpful. If 'long' delays means several minutes, running something along the lines of 'procstat -k $(pgrep -U dovecot -U doveauth)' every minute or so for a while might be one way to catch this, though this will collect a lot of data rather fast so you will need some way to locate the relevant entry.
Ben