dovecot - Nov 2012 - cannot update mailbox - unable to lock for exclusive access

Hi there,

We're using Dovecot version 1.0.7 and Postfix, and since upgrading our 
Linux box we're getting this in the maillog:

Nov  8 07:49:11 server1 postfix/local[27901]: 04B8E7081DA: 
to=<xyz at xyz.com>, orig_to=<abc at abc.com>, relay=local,
delay=19,
delays=0.07/0/0/19, dsn=4.2.0, status=deferred (cannot update mailbox 
/var/spool/mail/abc for user abc. unable to lock for exclusive access: 
Resource temporarily unavailable)

Postfix is currently set to:
mailbox_delivery_lock = fcntl, dotlock

Dovecot has this:
mbox_read_locks = fcntl
mbox_write_locks = fcntl dotlock

I've scoured the web and tried all kinds of different locking mechanisms 
and combinations to no avail.  The mail is eventually delivered but on a 
busy day this can take several hours.

In the evening it generally doesn't happen, which leads me to believe it 
occurs during the day when people have their mail clients open. 
However, this particular issue doesn't affect every user that has their 
mail client open, only some!

We currently have the mailboxes in mbox format - yes I know we should 
upgrade to maildir which we will eventually, however we've been using 
mbox for the last 10 years and this has only become an issue since 
upgrading.

What I have discovered this morning is a Dovecot connection that is open 
for 6 minutes before disconnection.  During this 6 minutes the above 
problem occurs (new mail cannot get an exclusive lock).  The same user 
will have connected and disconnected several times before and after, 
with a connection taking no more than a few seconds.  But it seems 
sometimes the connection is taking longer than it should and I suspect 
the problem lies here.

Please can anyone help!

Thank you,

G

On 11/8/2012 2:29 AM, 1st WebDesigns wrote:
> Hi there,
> 
> We're using Dovecot version 1.0.7 and Postfix, and since upgrading our
> Linux box we're getting this in the maillog:
1.0.7 is absolutely ancient and no longer officially supported.  You
need 1.2.x minimum, 2.x.x even better.  And you say you just recently
upgraded your Linux distro?  What planet do you live on son?  You're a
few light years behind current stable software.
> Nov  8 07:49:11 server1 postfix/local[27901]: 04B8E7081DA:
> to=<xyz at xyz.com>, orig_to=<abc at abc.com>, relay=local,
delay=19,
> delays=0.07/0/0/19, dsn=4.2.0, status=deferred (cannot update mailbox
> /var/spool/mail/abc for user abc. unable to lock for exclusive access:
> Resource temporarily unavailable)
The simple permanent fix to Postfix/Dovecot mbox locking issues is
switching from Postfix LOCAL to Dovecot LDA for mailbox delivery.  1.0.7
is before my time.  I do not know if LDA was available then.  Upgrade
and you'll have it, and you'll also fix other problems you're not
even
aware of yet.
> Postfix is currently set to:
> mailbox_delivery_lock = fcntl, dotlock
> 
> Dovecot has this:
> mbox_read_locks = fcntl
> mbox_write_locks = fcntl dotlock
LDA completely eliminates lock contention.

http://wiki.dovecot.org/LDA/Postfix
http://wiki2.dovecot.org/LDA/Postfix

-- 
Stan

Please always reply to the list, not individuals.

On 11/8/2012 4:17 AM, 1st WebDesigns wrote:
> On 08/11/2012 09:23, Stan Hoeppner wrote:
>> On 11/8/2012 2:29 AM, 1st WebDesigns wrote:
>>> Hi there,
>>>
>>> We're using Dovecot version 1.0.7 and Postfix, and since
upgrading our
>>> Linux box we're getting this in the maillog:
>>
>> 1.0.7 is absolutely ancient and no longer officially supported.  You
>> need 1.2.x minimum, 2.x.x even better.  And you say you just recently
>> upgraded your Linux distro?  What planet do you live on son? 
You're a
>> few light years behind current stable software.
>>
>>> Nov  8 07:49:11 server1 postfix/local[27901]: 04B8E7081DA:
>>> to=<xyz at xyz.com>, orig_to=<abc at abc.com>,
relay=local, delay=19,
>>> delays=0.07/0/0/19, dsn=4.2.0, status=deferred (cannot update
mailbox
>>> /var/spool/mail/abc for user abc. unable to lock for exclusive
access:
>>> Resource temporarily unavailable)
>>
>> The simple permanent fix to Postfix/Dovecot mbox locking issues is
>> switching from Postfix LOCAL to Dovecot LDA for mailbox delivery. 
1.0.7
>> is before my time.  I do not know if LDA was available then.  Upgrade
>> and you'll have it, and you'll also fix other problems
you're not even
>> aware of yet.
>>
>>> Postfix is currently set to:
>>> mailbox_delivery_lock = fcntl, dotlock
>>>
>>> Dovecot has this:
>>> mbox_read_locks = fcntl
>>> mbox_write_locks = fcntl dotlock
>>
>> LDA completely eliminates lock contention.
>>
>> http://wiki.dovecot.org/LDA/Postfix
>> http://wiki2.dovecot.org/LDA/Postfix
>>
> 
> Thanks for your reply.  We have upgraded from RHEL4 to RHEL5, so 1.0.7
> is the "stable" version that they provide
RHEL 5 is also ancient, released in March 2007, over 5 years ago.  The
current stable release is RHEL 6.3, released in June 2012.  What is the
valid reason preventing you from upgrading to the 6.x distribution?  The
packages in general in 6.x are 5 years newer than 5.x.  And given the
fact that RHEL runs miles behind the bleeding edge, you're way behind
the curve even with a recent RHEL distribution.

You can probably find a much newer version of Dovecot in an RPM
somewhere, and Postfix for that matter.  But it would be better for you
if you simply upgraded to RHEL 6.3.

-- 
Stan