On Mon, 2011-09-05 at 11:05 +0200, Jan-Frode Myklebust wrote:
We have quite a few frontend mail gateways that deliver incoming email trough our dovecot director (lmtp proxy) to the backend lmtp servers, and are seeing this logged on the frontend mail gateways:
Sep 5 10:51:56 mailgw1 postfix/lmtp[23443]: 0E2F41C01A: to=<me@example.com>, relay=loadbalancers.example.com[192.168.42.15]:24, delay=61, delays=0.02/0.3/31/30, dsn=4.4.0, status=deferred (host loadbalancers.example.com[192.168.42.15] said: 451 4.4.0 Remote server not answering (DATA output timeout) (in reply to end of DATA command))
It's a bit unclear to me if this leads to duplicate deliveries, or just delayed deliveries,
Possibly randomly either one. I'll need to start looking into these LMTP proxy bugs some day.. Although for 2.0.14 I improved the error messages a little. Is this from 2.0.14 or earlier?
but -- is there any way to limit the number of simultanous deliveries on either the dovecot director or the backend lmtp-servers ?
Will "process_limit=10" work for "service lmtp"?
It'll work for both directory and backend, yes. Although each lmtp process can also handle multiple clients. So you might also want to set client_limit=1. Actually that could be a good idea to try in any case to see if it helps with these problems.