[Dovecot] unable to lock for exclusive access: Resource temporarily unavailable

Robert Schetterer rs at sys4.de
Wed Sep 25 12:30:41 EEST 2013

Am 25.09.2013 11:17, schrieb npap at ecs.gr:
> Could you please provide more information about what you mean with
> Maildir format? I am not so familiar.
> Is it a quick and stable solution?
> Best Regards,
> Nikos
> Quoting Timo Sirainen <tss at iki.fi>:
>> 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.

Maildir is a standard specification


there is no easy answer what might be better to use at your side , this
depends on your setup ( how many mailboxes, how many mails , how big are
mailboxes etc , storagekind etc, traffic , how many pop3 vs imap logins )

your dovecot version is very old , you should upgrade or migrate in any case

Best Regards
MfG Robert Schetterer

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