[Dovecot] Maildir Subsystems

[Aaron Wiebe]

Greetings - new to the list, so apologies of I'm asking questions that
have been brought up before.

I work for a large email provider, currently using qmail, vpopmail and
courier-imap.  We tend to make fairly regular customizations of the
software, and if you folks have any knowledge of courier's code
layout, you probably can understand why we hate working on it.

Anyway, I am looking at the possibility of migrating to dovecot, after
a quick review of the code layout.  It is MUCH nicer to read.  But I
have a few specific questions:

1.  We customize our maildir system fairly heavily, and I'm wondering
where the maildir code is located.  Specifically, anywhere the app
actually does work on disk related to folders, mail content and
quotas.  While I have reviewed the code in brief, I thought it would
be easier to poke this list to get pointed in the right direction.

2.  Courier works quite well over NFS for us, and I'm curious why your
documentation covers NFS more specifically.  What aspects of the
filesystem are normally used that don't translate easily to work over
NFS? Do you use stuff like inotify or atimes?

3.  If anyone has any suggestions on how to migrate tens of thousands
of imap users from courier to dovecot in a few hour window, I'd like
to hear them :)

Thanks,
Aaron Wiebe