Re: [Dovecot] lmtp performance

A particular reply (not to the list) has told me to try:

" Add to service lmtp: process_min_avail = 20 "

And yes, it works (unless for me), so I want to share it with everybody.

Have not exactly measured performance but this morning have seen over 1400 messages/minute with lmtp under heavy load.

What the "process_min_avail = 20" in service lmtp (or anywhere else) exactly imply? cannot find a reference in wiki2 . I suppose it means than 20 lmtp processes are always open waiting for new connections and so reducing startup latency, isn't it?

Thank you.

On Mon, Oct 17, 2011 at 6:06 AM, Juan Carlos Sanchez mailto:juancarlos.sanchez@upm.es> wrote:

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@upm.es <mailto:postmaster@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@upm.es <mailto:postmaster@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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Juan Carlos Sanchez Hernandez Universidad Politecnica de Madrid