[Dovecot] lmtp performance

[Juan Carlos Sanchez]

Hello:

In the process of migration from version 1.2 to 2.0 have tried to use 
lmtp instead of lda as delivery agent.

But unfortunately througput we get is poor with lmtp compared to lda.
In peak times with lda we are able to deliver over 1800 messages/minute 
(high I/O but not affecting service) but if we switch to lmtp cannot 
deliver more than 300 mess/minute (very low I/O).

This is enough for normal work but low under heavy load (distribution 
lists messages sometimes stay queued for 4 hours before deliver).

We have arround 50000 boxes and use postfix as MTA

How to increase lmtp performance?


dovecot config for lda and lmtp:

protocol lda {
   auth_socket_path = /usr/local/var/run/dovecot/auth-master
   info_log_path = /var/log/mail/dovecot_deliver.log
   log_path = /var/log/mail/dovecot_deliver.log
   mail_plugins = quota sieve zlib
   postmaster_address = postmaster at upm.es
   sendmail_path = /usr/lib/sendmail
}

protocol lmtp {
   info_log_path = /var/log/mail/dovecot_deliver.log
   log_path = /var/log/mail/dovecot_deliver.log
   mail_plugins = quota sieve zlib
   postmaster_address = postmaster at upm.es
   sendmail_path = /usr/lib/sendmail
}

In postfix I have:

mailbox_transport = lmtp:unix:private/dovecot-lmtp



Thanks in advance.

-- 

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Juan Carlos Sanchez Hernandez
Universidad Politecnica de Madrid
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