dovecot - Aug 2007 - Dovecot fails almost every 20 minutes exactly

Hi all,

We just set up our new mail servers using Postfix and Dovecot.  We have 
implemented a load balanced solution to where our two mail servers have 
a common NFS share.

Everything is working great.  Everything but Dovecot for the most part.  
In testing, Dovecot was great.  Now that we're in the production 
environment, we've noticed that every 20 minutes, Dovecot will stop 
running.  But it gets even weirder - it appears that Machine A will 
stop, then 20 mins later after we issue a 'service dovecot restart', 
Machine B will stop.  Then the whole process starts over when we restart 
Dovecot on Machine B.

I can't see anything out of the ordinary in the log files either.  I'm 
at a loss as to what's going on.

Here's my dovecot -n:

################################
# 1.0.3: /etc/dovecot.conf
listen: *
ssl_cert_file: /usr/share/ssl/hermes.garlic.com/hermes.garlic.com.cert.pem
ssl_key_file: 
/usr/share/ssl/hermes.garlic.com/hermes.garlic.com.privatekey.pem
login_dir: /var/run/dovecot-login
login_executable(default): /usr/libexec/dovecot/imap-login
login_executable(imap): /usr/libexec/dovecot/imap-login
login_executable(pop3): /usr/libexec/dovecot/pop3-login
first_valid_uid: 200
mail_location: maildir:/home/%u/Maildir:INDEX=MEMORY
maildir_copy_with_hardlinks: yes
maildir_copy_preserve_filename: yes
mail_executable(default): /usr/libexec/dovecot/imap
mail_executable(imap): /usr/libexec/dovecot/imap
mail_executable(pop3): /usr/libexec/dovecot/pop3
mail_plugin_dir(default): /usr/lib/dovecot/imap
mail_plugin_dir(imap): /usr/lib/dovecot/imap
mail_plugin_dir(pop3): /usr/lib/dovecot/pop3
auth default:
  user: dovecot-auth
  username_format: %Lu
  passdb:
    driver: pam
  userdb:
    driver: passwd
  socket:
    type: listen
    client:
      path: /var/spool/postfix/private/auth
      mode: 432
      user: postfix
      group: postfix
################################

Any ideas what could be wrong?  I don't think that setting up a cron to 
restart both dovecot servers is an idea solution - I'm hoping this is an 
easy fix.

Thanks in advance.

Patrick

On Sunday, August 19 at 02:13 PM, quoth Patrick - South Valley
Internet:
> Now that we're in the production environment, we've noticed that 
> every 20 minutes, Dovecot will stop running.
Meaning what? Is the dovecot process still alive? Is the service 
unresponsive? Is it just not allowing logins?

Is the shared NFS store the only thing shared between the two? Is 
there a load-balancer in front of the machines?
> I can't see anything out of the ordinary in the log files either.  
What are the last couple entries in the log files when it "stops"? The
same things every time, or something different every time?

~Kyle
-- 
If Mr. Einstein doesn't like the natural laws of the universe, let him 
go back to where he came from.
                                         -- Robert Benchley (1889-1945)
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The issue had to do with PAM.  I was getting zombie processes.

adding 'args = blocking=yes'  to the passdb pam area fixed the issue.

Thanks for the response.

Patrick





Kyle Wheeler wrote:
> On Sunday, August 19 at 02:13 PM, quoth Patrick - South Valley Internet:
>> Now that we're in the production environment, we've noticed
that
>> every 20 minutes, Dovecot will stop running.
>
> Meaning what? Is the dovecot process still alive? Is the service 
> unresponsive? Is it just not allowing logins?
>
> Is the shared NFS store the only thing shared between the two? Is 
> there a load-balancer in front of the machines?
>
>> I can't see anything out of the ordinary in the log files either.  
>
> What are the last couple entries in the log files when it
"stops"? The
> same things every time, or something different every time?
>
> ~Kyle