mbox 2 Maildir

[Joseph Tam]

Tamas Hegedus, 29.01.19:

>> * Configuration uses mail_location = mbox:~/mails
>> * setup per-user mail location and do for each user individually in a 
>> serial manner:
>> -- doveadm sync maildir:~/Maildir; mbox is synced to Maildir, long running 
>> time
[1]
>> -- doveadm sync maildir:~/Maildir; rerun to do it for new messages (fast)
>> -- add USER to userdb and set extra field to maildir:~/Maildir
>> users not present in the userdb should default to dovcot default; 
[2]
>> the conditionally optional: doveadm auth cache flush

More or less how I would plan a migration, but to be fanatically safe
and avoiding race conditions where a user could be manipulating their
mailbox or new having mail delivered, I would put some service mutex
between [1] and [2].

By that I mean at [1]

 	a) tempfail any incoming mail for that user; and

 	b) kick the user off IMAP/POP and make sure they can't log back
 	in during the final synching.  (Add them to separate deny userdb?)

After the final sync [2], undo these steps.

Joseph Tam <jtam.home at gmail.com>