[Web-cyradm] pros/cons of deliver vs. lmtp

[Leon Kolchinsky]

Hello All,

1) After I've started to get these errors:
--------------------------
Jan  5 15:09:10 mail postfix/pipe[24050]: AFC901243F5:
to=<pieterv at mydomain.ac.il>, orig_to=<pieterv at mydomain.ac.il>, relay=cyrus,
delay=1000, status=bounced (Command time limit exceeded:
"/usr/lib/cyrus/bin/deliver")
Jan  5 15:23:32 mail postfix/pipe[24390]: 87C1D12C53:
to=<pieterv at mydomain.ac.il>, orig_to=<pieterv at mydomain.ac.il>, relay=cyrus,
delay=1000, status=bounced (Command time limit exceeded:
"/usr/lib/cyrus/bin/deliver")

And one of my users started to complain that he didn't get e-mails from
outside, I did a little digging in the net, and decided to switch to lmtp
transport (I've also increased command_time_limit like this: postconf -e
"command_time_limit = 3600s"):

So, I did this change:
-----------------
in /etc/cyrus.conf:
  lmtpunix      cmd="lmtpd" listen="/var/lib/imap/socket/lmtp" prefork=0
maxchild=20
  
in /etc/postfix/master.cf (check if exist):
lmtp      unix  -       -       n       -       -       lmtp

/etc/postfix/main.cf (this is there I actually made a change):
#change mailbox_transport = cyrus to
mailbox_transport = lmtp:unix:/var/lib/imap/socket/lmtp

/etc/imapd.conf (this is there I actually made a change):
lmtpsocket: /var/lib/imap/socket/lmtp


I also had to add mail and postfix to the same group like:

check the group of cyrus user:
# cat /etc/passwd| grep cyrus
cyrus:x:96:12:User for cyrus-imapd:/usr/lib/cyrus:/bin/bash

make sure that mail and postfix in the same group:
# cat /etc/group| grep 12
mail:x:12:mail,postfix

This helped to get rid of these 2 errors:
a) Jan  7 13:53:58 mail postfix/lmtp[1750]: C8E8412C67B:
to=<azy at mydomain.ac.il>, orig_to=<azy at mydomain.ac.il>, relay=none, delay=1,
status=deferred (connect to
/var/lib/imap/socket/lmtp[/var/lib/imap/socket/lmtp]: Permission denied)
b) pop3[4451]: unable to open Berkeley db /etc/sasldb2: Permission denied
Here I also did:
# chgrp mail /etc/sasldb2

2) Now I've noticed a real performance boost and "Command time limit
exceeded" error disappeared.

3) My question to the list is:
Could someone explain the pros/cons of deliver vs. lmtp?

I've seen these 2 topics:
http://marc.theaimsgroup.com/?l=info-cyrus&m=108681315921664&w=2
http://blog.gmane.org/gmane.mail.postfix.user/day=20030121

And it's obvious that there is a performance boost, using lmtp transport,
according to this - 
unix:lmtp transport:
This uses the same mail delivery process multiple times.

cyrus deliver transport:
This executes the /usr/cyrus/bin/deliver file once for every mail
delivery.

So, why web-cyradm uses cyrus deliver transport (in the docs) as it's
default?
Is there any other issues I'm not aware of?



Best Regards,
Leon Kolchinsky