On 7/29/2013 2:30 AM, Jan Behrend wrote:
You cannot use the LDA method if SMTP and IMAP services reside on different machines, which would be the case in larger scale mail system setups.
Which brings up an interesting point. With a single LMTP daemon on the Dovecot server communicating via a single socket with the upstream MTA over the wire, it would stand to reason that message throughput rate may be limited by serialization in the LMTP request/reply chain. There is no parallelism, and thus there is relatively high latency.
In the case of LDA with an SMTP MTA on the local box, the potential exists for very high parallelism, and thus elimination of the latency in serial delivery over a single socket with LMTP.
So in theory, while LDA in this scenario would consume far more resources with a very high message load, one should be able to attain much higher message throughput. I say in theory because I've not tested this head to head.
-- Stan