dovecot - Sep 2013 - unable to lock for exclusive access: Resource temporarily unavailable

Dears,

 

We have a mail server (RHEL 6.0, Postfix and Dovecot 1.0.7).

The output of dovecot -n is the following:

 

# 1.0.7: /etc/dovecot.conf

protocols: pop3

login_dir: /var/run/dovecot/login

login_executable: /usr/libexec/dovecot/pop3-login

mail_location: mbox:~/mail:INBOX=/var/mail/%u

mail_executable: /usr/libexec/dovecot/pop3

mail_plugin_dir: /usr/lib/dovecot/pop3

pop3_client_workarounds: outlook-no-nuls oe-ns-eoh

auth default:

  passdb:

    driver: pam

  userdb:

    driver: passwd

 

 

During the last days we face the following problem:

There is great delay in the delivery of the emails. Some seem to not be
delivered at all. Issuing the mailq command we get the following message for
almost all the email accounts:

(cannot update mailbox /var/mail/xyz for user xyz. unable to lock for
exclusive access: Resource temporarily unavailable)

 

Please send to me any suggestions, because I cannot resolve it and I receive
a lot of pressure.

 

Best Regards,

 

Nikos

On 25.9.2013, at 10.27, Nikos Papadopoulos <npap at ecs.gr> wrote:
> We have a mail server (RHEL 6.0, Postfix and Dovecot 1.0.7).
> 
> mail_location: mbox:~/mail:INBOX=/var/mail/%u
> 
> There is great delay in the delivery of the emails. Some seem to not be
> delivered at all. Issuing the mailq command we get the following message
for
> almost all the email accounts:
> 
> (cannot update mailbox /var/mail/xyz for user xyz. unable to lock for
> exclusive access: Resource temporarily unavailable)
mbox format is problematic in this way. Newer Dovecot versions (v2.x) do some
extra work to unlock the mbox earlier with POP3. That might help you. Or you
could switch to Maildir format where this isn't a problem. I'm not sure
why it started happening only now and not earlier. Perhaps the POP3 clients are
downloading mails more slowly, perhaps you're getting more mail and things
are running slower than before.