su - cyrus
mkdir /var/imap/db

but now I'm failing at:
Nov 2 23:18:48 pepe postfix/lmtp[98941]: 9983C21D: to=<xxxxxxxxx>, relay=none, delay=2, status=deferred (connect to /var/imap/socket/lmtp[/var/imap/socket/lmtp]: Socket operation on non-socket)

Google isn't helping yet...