Dovecot infrastructure

[Simone Marx :: Edinet Srl]

Hi,
I would need some suggestion for a dovecot based mail infrastructure.
Actually, only one server (with dovecot sendmail amavis spamassassin 
clamav etc etc) is no longer enouth, so I thought I would put on a more 
complex infrastructure on different servers.

But I do not know a few things.
I was thinking about partitioning users on 3-4 servers with dovecot 
(imap / pop3) and dovecot-lda (no networked filesystem between them) and 
then configuring 1-2 servers with dovecot director and 1-2 servers for 
SMTP with postfix.
It is not clear how the director will map user -> server to be used and, 
in a user virtualization context (maybe on MySQL) what is the owner / 
permissions I should give to home folders where I will store mail

Thank you.
Simone.