[luau] mbox vs Maildir

[R. Scott Belford]

Like many of us, I have been enjoying reasonably spam free, sorted, and
web-accessible mail via
exim/fetchmail/procmail/spamassasin/imap/squirrelmail.  It has been a
delight.  Not content with good enough, I have been toying with the idea of
using courier-imap instead of uw-imap.  Courier uses the maildir format
apparently developed by DJB for qmail, and Uw-imap uses the standard mbox
format.  The way I understand it, maildir can be much less processor
intensive for large or multiple mailboxes.

On a test box I have begun the process.  Great documentation has been found
via our friend Google.

http://talk.trekweb.com/~jasonb/articles/exim_maildir_imap.shtml

But I am having trouble.  My mail is being picked up by fetchmail and exim
is delivering it to /var/mail/username.  The thing is, there is no mail in
my inbox when using an imap client.  Courier wants the message to be in the
$home/Maildir/cur folder.  When I send mail from the localhost to a user on
the machine, the mail ends up in that user's Maildir as it should.  When I
have fetchmail retrieve mail for that user, the spam is processed by
procmail to its respective Maildir box, but the mail goes to
/var/mail/username instead of into the Maildir.

I am pointing my finger at exim or procmail.  My exim.conf file has the
following added to it:
directory=${home}/Maildir
  maildir_format = true
  prefix = ""

under the local_delivery section.  When that did not work, I thought the
problem was with my procmail recipe.  I added to the top of procmail

MAILDIR=$HOME/Maildir
DEFAULT=$MAILDIR
LOGFILE=$HOME/procmail.log
VERBOSE=off
SPAM=$HOME/Maildir/.Spam/

with the idea that once exim passed the mail to procmail, procmail needed to
know that I was using the maildir format.  Still no success.  I had been
using .forward to call procmail, and I have tried adding the mda line to
fetchmail to call procmail.  My mail still goes to /var/mail.

After setting up another account without procmail, fetchmail gets the mail
and exim puts it into the Maildir.  When using an imap client, I see the
mail in my Inbox.  It seems that there is some trouble with how Procmail is
handling the messages.  I guess that I could take procmail out of the
picture and call spamassassin through exim, but then I lose the sorting
capabilities of procmail.

Has anyone made a conversion like this, and if so, did you have any trouble?
It seems from the lack of hits on Google that I must have done something
wrong, but I just cannot track it down.  If you made it this far and have a
suggestion, I would appreciate it.  If my verbose message is missing some
detail, please let me know and I will elaborate.

--scott