[Dovecot] limit number of simultaneous lmtp deliveries ?

[Jan-Frode Myklebust]

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 at 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, 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"? 


  -jf