dovecot - Oct 2007 - Error: net_connect(/var/run/dovecot/auth-master) failed: Resource temporarily unavailable

I'm using deliver (1.0.5) with Postfix (2.1.6). I made a test for a few
minutes in a moderated busy server. While most mails was delivered, a
lot of them failed with this error:

deliver(userfoo): Oct 15 09:58:31 Error:
net_connect(/var/run/dovecot/auth-master) failed: Resource temporarily
unavailable

Sounds to me something like not enough auth-master to answer every
concurrent deliver.

Any hint?

Regards,
maykel

PD: If there any other info I could give let me know.

On 10/15/2007, Maykel Moya (moya at infomed.sld.cu)
wrote:
> I'm using deliver (1.0.5) with Postfix (2.1.6).
<snip>
> Any hint?
May not be the cause - but postfix 2.1.6 is - well - *ancient*...

I'd make upgrading a priority, even it didn't fix the problem...

-- 

Best regards,

Charles

> El lun, 15-10-2007 a las 10:41 -0400, Charles Marcus escribi?:
> > On 10/15/2007, Maykel Moya (moya at infomed.sld.cu) wrote:
> > > I'm using deliver (1.0.5) with Postfix (2.1.6).
> > 
> > <snip>
> > 
> > > Any hint?
> > 
> > May not be the cause - but postfix 2.1.6 is - well - *ancient*...
> > 
> > I'd make upgrading a priority, even it didn't fix the
problem...
> 
> I'd upgraded postfix to 2.4.5. Although not sure if it helps I also
> raised auth_worker_max_count. Up to this moment I haven't had
experience
> the error again.
Well, there it's, again. Postfix, by defaults, don't do more than 100
concurrent deliveries with the same transport, local in my case.

I raised up auth_worker_max_count to 128, to accomodate 100 potential
concurrent deliveries plus some pop3/imaps clients.

The problem appears with certain frequency. There is no other info in
the log besides the error notification.

FWIW:
I have auth_debug enabled. In normal operation I can see the LDAP
queries:
dovecot: Oct 16 09:46:14 Info: auth(default): ldap(foo,x.y.z.w): pass
search: base=ou=users,dc=foo,dc=org scope=subtree filter=(uid=foo)
fields=uid,userPassword,sldMailbox

nevertheless, next to net_connect errors, the ldap related line is
something like

dovecot: Oct 16 09:46:14 Info: auth(default): ldap(foo,x.y,z,w): unknown
user

in both cases, the user don't exist in the directory.

Don't know is this could be something with the same nature of[1].

My config
--
base_dir = /var/run/dovecot-ldap

# IO optimizations
fsync_disable = yes
dotlock_use_excl = yes
maildir_copy_with_hardlinks = yes
maildir_stat_dirs = no
maildir_copy_preserve_filename = yes

protocol lda {
  postmaster_address = bar at foor.org
  auth_socket_path = /var/run/dovecot/auth-master
  mail_plugins = quota

  # http://wiki.dovecot.org/MailLocation/LocalDisk
  fsync_disable = yes
}

auth default {
  mechanisms = plain

  auth_worker_max_count = 128

  socket listen {
    master {
      path = /var/run/dovecot/auth-master
      mode = 0660
      user = dovecot
      group = nusers
    }
  }

  passdb ldap {
    args = /etc/dovecot/dovecot-ldap.conf
  }
  passdb pam {
  }

  userdb ldap {
    args = /etc/dovecot/dovecot-ldap.conf
  }

  userdb prefetch {
  }

  userdb passwd {
  }

  user = root
}
--

Regards,
maykel

[1] http://www.dovecot.org/list/dovecot/2007-October/026069.html