[Dovecot] Question about mail storage

[Stewart Dean]

I am in the throes of trying to understand all the issues of
transforming an old UW Imap server with mbox (I think) INBOX format
running sendmail and procmail serving 3500 users to dovecot and maildir
format.  Currently, the folders are under ~/mail and the INBOXes are
under /var/spool/mail.
If I understand correctly, the typical default Dovecot/maildir format
installation will have both the INBOX and folders (prefixed with a
period), so they take the format: .<foldername>) under ~/Maildir.
Right?  I am planning to do a gradual phaseover of one chunk of ids at a
time........

"I am in a maze of twisty tunnels, all alike. A dwarf runs by........"

Some questions:
1) In the UW IMap docs, formats.txt discusses a bunch of different
mailbox formats.  I am unclear as to whether I currently have what
Crispin describes at .unix format or .mbx format.
> . unix	This is the traditional UNIX mailbox format, in use for nearly
> 	30 years.  It uses a line starting with "From " to indicate
> 	start of message, and stores the message status inside the
> 	RFC822 message header.
>
> 	unix is not particularly efficient; the entire mailbox file
> 	must be read when the mailbox is open, and when reading message
> 	texts it is necessary to convert the newline convention to
> 	Internet standard CR LF form.  unix preserves UIDs, and allows
> 	the creation of keywords.
>
> 	Only one process may have a unix-format mailbox open
> 	read/write at a time.
>   
and ...
> . mbx	This is the current preferred mailbox format.  It can be
> 	handled quite efficiently by c-client, without the problems
> 	that exist with unix and mmdf formats.  Messages are stored
> 	in Internet standard CR LF format.
>
> 	mbx permits shared access, including shared expunge.  It
> 	preserves UIDs, and allows the creation of keywords.
How do I tell them apart? Alternately, how do I tell if what I now have
(some sort of one big single-file INBOX) is mbox?  Or is what he's
referring to as unix just mbox

2) How to change Where Things End Up
a) The users' ~/.procmailrc pretty much consists of: MAILDIR=$HOME/mail
Am I correct in assuming that this should be changed to:
MAILDIR=$HOME/Maildir/
?
b) Mail appears to end up in /var/spool/mail/<username> because that's
the procmail default (ORGMAIL).
To redirect individual users (because this will be a gradual
changeover), am I correct in assuming that putting:
DEFAULT=$HOME/Maildir/
in ~/.procmailrc will redirect incoming mail?

3) I see that, in the default configuration, /everything/ will now be
under ~/Maildir and thus in the home directories.  Is there a reason to
get away from a separate INBOX directory (we use /var/spool/mail)?  I'd
have to rebuild the homedir filesystems to accommodate the INBOX
demands.  This isn't all that big a deal, I'd like to understand the
rationale..or should I just bow to the inevitable?

4) Pardon my stupidity, but how is the Dovecot INBOX under maildir++
organized?
a) Is it a separate directory under ~/Maildir (say ~/Maildir/INBOX or
some such) that has a separate file for each message or
b) are the INBOX messages just mixed in with the folders under
~/Maildir.  If so, how are they differentated?


Enlighten my ignorance,.please!  I've been reading docs today until my
brain feels like custard, but I couldn't seem to get clear definitive
answers to these questions........

Thanks in advance.

-- 
====
Stewart Dean, Unix System Admin, Henderson Computer Resources
Center of Bard College, Annandale-on-Hudson, New York  12504
sdean at bard.edu  voice: 845-758-7475, fax: 845-758-7035