[Dovecot] Smooth mailbox to maildir migration

[Harry Lachanas]

Luciano Mannucci wrote:
> Hi all,
>
> I have a postfix+procmail+dovecot installation, now running basicaly
> on pop3 hence mailbox format, with few thousand users and less than
> twenty gigabytes mail.
> I need to move all of them to maildir, to take advantage of IMAP
> subfolders that do not work with mbox format (so I'm told :).
>   
Also take into consideration that you will need much more disk space for 
this ....

Harry
> Of course I cannot safely stop the service for more than a bunch of
> seconds...
>
> What I'm about to do:
>
> create a second dovecot instance to cope with imap client configured
> for maildir (and possibly pop3 on another port for those using both),
> which means a dovecot launched with -c /path/to/alternate.conf and a
> new /etc/init.d/dovecot2-theRevenge having the proper -i option given
> to startproc in order to make it ignore the other instance.
>
> for each user:
>
> convert the mailbox with some sort of mb2mb (which is the better one?)
>
> create a .procmailrc with a proper DEFAULT= bearing the magic trailing
> slash indicating maildir to procmail for each converted user.
>
> And I'm done...
>
> Have I forgotten something?
> Is there a better way?
> Any one else tryed such a thing?
>
> Cheers to all,
>
> luciano.
>