[Dovecot] Improving lmtp performance
Joseba Torre
joseba.torre at ehu.es
Thu Feb 3 11:53:46 EET 2011
El Thursday 03 February 2011, Stan Hoeppner <stan at hardwarefreak.com> dijo:
> You've posted no log data. It's pretty difficult to diagnose problems
> without log entries. Do you just want us to guess?
Yes, I now may mail was pretty vague, but so was the issue. I posted no logs
because I saw nothing really useful in them; the only sympton was the slow
delivery rate.
Postfix's was full of messages going to the active queue
Feb 1 12:43:20 server1 postfix/qmgr[8916]: ED7236CDC1:
from=<noreply at mydomain.com>, size=8314, nrcpt=1 (queue active)
Feb 1 12:43:21 server1 postfix/smtpd[9427]: 289306CDC3:
client=lgux66.lgp.mydomain.com[10.0.100.71]
Feb 1 12:43:21 server1 postfix/cleanup[12768]: 289306CDC3: message-
id=<moodlepost24182 at moodle2.mydomain.com>
Feb 1 12:43:21 server1 postfix/qmgr[8916]: 289306CDC3:
from=<noreply at mydomain.com>, size=8313, nrcpt=1 (queue active)
and some occasional delivery
Feb 1 12:43:23 server1 postfix/lmtp[9549]: 0C5866CF37:
to=<cdmorales001 at server1.mydomain.com>,
relay=server1.mydomain.com[/var/spool/postfix/private/dovecot-lmtp],
delay=854, delays=37/668/140/9.8, dsn=2.0.0, status=sent (250 2.0.0
<cdmorales001 at server1.mydomain.com> upb1FNftR03cIgAAl0Wliw Saved)
or delivery error
Feb 1 12:43:21 server1 postfix/lmtp[9554]: 1C2946CF92:
to=<aanton007 at server1.mydomain.com>,
relay=server1.mydomain.com[/var/spool/postfix/private/dovecot-lmtp],
delay=815, delays=1.6/664/141/8
.9, dsn=4.2.2, status=SOFTBOUNCE (host
server1.mydomain.com[/var/spool/postfix/private/dovecot-lmtp] said: 552 5.2.2
<aanton007 at server1.mydomain.com> Quota exceeded (mailbox for user is full) (
in reply to end of DATA command))
(softbounce was activated to prevent bounces because of misconfigurations)
Dovecot's was as usual, with some
Feb 1 13:18:09 server1 dovecot: lmtp(8924, llasa002 at server1.mydomain.com):
ArX1FNftR03cIgAAl0Wliw: msgid=<CDPMA-WI015feT9L0Yd00060a97 at CDPMA-
WI01.infoempleo.com>: saved mail to INBOX
Feb 1 13:18:22 server1 dovecot: lmtp(8924, aarruti011 at server1.mydomain.com):
FbX1FNftR03cIgAAl0Wliw: msgid=<moodlepost24217 at moodle2.mydomain.com>: saved
mail to INBOX
Feb 1 13:18:23 server1 dovecot: lmtp(8924, jlopez078 at server1.mydomain.com):
E7X1FNftR03cIgAAl0Wliw: msgid=<moodlepost24182 at moodle2.mydomain.com>: saved
mail to INBOX
(this was the actual delivery rate: in this case, 3 messages in 14 secs)
My question was if this is the expected behavior, or if lmtp was expected to
behave a lot better with just 1 process (that was what I expected, at least),
and if my solution was usual or at least correct. It was not a practical
question -my system is working fine now-, but a more teorical one. I was
expecting answers like
"I'm using a very simple conf for lmtp in a busy server, something similar to
protocol lmtp {
mail_plugins = quota sieve
}
service lmtp {
unix_listener /var/spool/postfix/private/dovecot-lmtp {
group = postfix
mode = 0660
user = postfix
}
}
and it's working fine for me, so look in other place".
>
> > Also, if this is a common problem, may be something should appear in
> > http://wiki2.dovecot.org/LMTP
>
> That's a bit premature. The problem could just as likely be a Postfix
> configuration error. Get us some logs from both Postfix and Dovecot for
> the previous configuration with the slow performance.
I agree. That's why a say "if this is a common problem".
>
> Are both Postfix and Dovecot running in the same VM guest OS instance or
> two separate VM guests? Are you running elaborate Sieve scripts? Are you
> running AV/AS in Dovecot? Anything relatively CPU heavy in Dovecot on a
> per message basis?
Yes, everything was in the same VM guest, no elaborated sieve scripts that I
know (I've just recreated them with horde's ingo, and I'm sure they are quite
basic), no AV/AS, and system's load was normal, with some i/o wait, but in my
experience this is usual in VM guests.
Thanks.
--
Joseba Torre. Vicegerencia de TICs, área de Explotación
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