[Dovecot] Dovecot design-question

[Werner]

Hi,

>>> - It's probably the best idea to direct SMTP and POP/IMAP always to
>>> the same server behind the loadbalancer (because dovecot-deliver is
>>> used which updates indexes?)
>>
>> like mentioned on the website, but "would it be possible without nasty
>> errors" ?
> 
> If both servers access index files at the same time, it's going to cause
> errors.

I'm currently running Tests for concurrent delivery via dovecot-deliver to
a mailbox on a nfs-share with postal. And so far, i did not notice any problems
when incoming SMTP is directed via LVS to two Mailservers which in parallel
drop messages with dovecot-deliver to the users mailbox and updates dovecots
index.files (btw. dovecot 1.2.10 in use, mail_nfs_storage = yes, mail_nfs_index = yes).

The only thing I've found so far:

Feb 16 17:33:46 cmx2 postfix/pipe[24221]: DD3F118A22A: to=<werner at example.com>, relay=dovecot, delay=3.4, delays=0.75/0/0/2.6, dsn=4.3.0,
status=deferred (temporary failure. Command output: Internal error occurred. Refer to server log for more information. [2010-02-16 17:33:43])

This message was delivered in the next run to the users mailbox.

> active/passive is guaranteed to work at least. Or any setup where a
> user's indexes aren't accessed at the same time by two machines.

We'd like to direct IMAP/IMAPS/POP/POPS/HTTP/HTTPS to one machine only but SMTP
should be directed via LVS to both servers in parallel. And regarding to the
mentioned tests - i assume this will work.

Any notes/annotations from you guys ? Why don't I experience NFS/Index-issues?

Regards,
Werner