[Dovecot] dovecot & OCFS2 Cluster
robert at schetterer.org
Wed Apr 27 11:28:25 EEST 2011
Am 27.04.2011 00:50, schrieb Joseph Tam:
> Robert Schetterer <robert at schetterer.org> writes:
>>> Anyway, why use lmtp over lda ?
>> i.e avoid backscatter by overquota
> A clarification on this: backscatter (or rather, ambiguous NDR notices
> that claim many users are over quota rather than just one) is a result
> of a local mailer that support multiple recipient delivery in one
> invocation, but can only return one result code to the MTA.
> Since Dovecot's deliver-lda does not support multiple recipient delivery,
> this is not a problem.
> LMTP can support multiple deliveries of the same message per invocation,
> but replies with individual SMTP codes to avoid the above problem.
> It can take advantage of this to efficiently implement single instance
> storage if it is enabled.
in my understanding lmtp acts more like a mta
so overquota "reject" can be send during smtp income stage i.e with
postfix, to the sender client
with lda this isnt possible cause the the mta does give the whole mail
to lda which and mta send "recieved" to the sender client
( so the bounce must be send later by binary sendmail etc )
whatever this is the behavior i ve tested in my setups,
may Timo correct me if i fail here
>> performance should better too
> Apart from multiple deliveries or SIS, I'm not sure this is true, or
> significant if it were.
yes this should be meassured, youre right i dont know too if its really
performance relevant, but multiple deliver is nice to have anyway, why
should not use it
> Joseph Tam <jtam.home at gmail.com>
however i see no reason to use lda longer in my setups as lmtp exits
youre right the backscatter case is really rare anyway
MfG Robert Schetterer
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