multi pronged upgrade/migration
This question touches on far more than Postfix, so I hope it doesn't offend
anyone being slightly OT.
A little background may help:
I built my current Postfix host in late 2005 as a single purpose
firewall/gateway to sit in front of an old Ms Exch server, on which I've
archived email since 2000. The Postfix firewall has functioned in this mode for
4+ years. It's running on a Debian system up to date at 5.0.3 with all patches
installed and a custom kernel, 18.104.22.168. I'm running the Debian Lenny Postfix
2.5.5-1-1 package which I upgraded within the past few of months from 2.3.8
during the upgrade to Lenny. I never configured local mail delivery on this
host as I installed Postfix on build day in '05 and set it to relay only. I
have no experience with standard *nix mailbox or maildir formats, but I've
recently read up a little bit on the basics of both at the Dovecot website.
What I want to do is:
1. Switch Postfix from relay mode to local delivery
2. Convert entries in relay_recipients to aliases pointing to a local Unix user
3. Select an appropriate mailbox format, location, and filessytem
4. Install an appropriate IMAP/POP server daemon package
5. Migrate current emails and folders to the new Postfix/IMAP combo
6. What have I overlooked?
I know basically "how" to perform change  but the details depend on [2/3],
which I need advice on. From what I've read on this list I think I'd like to
use Dovecot for IMAP. What is the best way to reconfigure Postfix to drop mail
in the best format and location for Dovecot (mbox vs maildir)? My current
Postfix spool is on / which has ~30GB free, ext2 FS. If preferable I can create
a new partition formatted with any appropriate filesystem, mount that and have
Postfix/Dovecot dump new mail there, along with storing the IMAP mail and
folders. I've already migrated most of the mail and folders from the old IMAP
server to local Thunderbird folders on my PC, so migrating those to the new IMAP
server should be fairly straight forward once I have the new IMAP server up and
Of note, I have quite a few current IMAP folders with a thousand emails in each,
and one folder with over 10,000 emails. Would mbox or maildir format be better
here, and does this effect Postfix in any way, or only the IMAP server?
Thanks for any/all advice, and again, sorry if some of this if OT. I know many
here run Dovecot and other IMAP servers alongside Postfix so I figured you might
have some pointers.
Happy new year to all.