[Dovecot] Lots of LMTP errors Remote server not answering (DATA output timeout) (in reply to end of DATA command))

[Angel L. Mateo]

El 08/07/11 14:04, Angel L. Mateo escribió:
> El 08/07/11 12:18, Angel L. Mateo escribió:
>> Hello,
>>
>> I have configured two dovecot servers with director acting as
>> lmtp/imap/pop proxy server with 8 dovecot backend servers.
>>
>> In our test environment we had no problem, but when we migrated to
>> production environment, our mail list server (it delivers mail through
>> lmtp) is having a lot of errors like this:
>>
>> 451 4.4.0 Remote server not answering (DATA output timeout) (in reply to
>> end of DATA command))
>>
>> Proxy and backend servers are not loaded.
>>
>> Any idea?
>>
> By now, I think I have resolved the problem. We have limited the rate at
> what list server delivers mail to dovecot. The default postfix
> configuration is:
>
> lmtp_destination_concurrency_limit = 20
> lmtp_destination_recipient_limit = 50
>
> that is,
>
> a maximum of 20 lmtp concurrence connections with a maximum of 50
> recipients per connection. We have decrease to 5 and 10 and since then
> we have no more data output timeout errors.
>
>
	This wasn't a fix. Although it works temporally and alleviate the 
problem, it didn't completely fixed and I get sporadic errors like:

Jul 11 13:46:25 xenon14 postfix/lmtp[7063]: A0ECA5D49E: 
to=<user at mydomain.com>, relay=pop.um.es[155.54.212.106]:24, delay=599, 
delays=569/0/0/30, dsn=4.4.0, status=deferred (host 
pop.um.es[155.54.212.106] said: 451 4.4.0 Remote server not answering 
(DATA output timeout) (in reply to end of DATA command))

	Any idea of what is the reason for this?

-- 
Angel L. Mateo Martínez
Sección de Telemática
Área de Tecnologías de la Información       _o)
y las Comunicaciones Aplicadas (ATICA)      / \\
http://www.um.es/atica                    _(___V
Tfo: 868887590
Fax: 868888337