[Dovecot] Smooth mailbox to maildir migration

[Dirk Essl]

On 10.02.2009 16:49 Uhr, Luciano Mannucci wrote:
> Hi all,

Hi,

> 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 :).
> 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?

I do all migrations with perdition (imap proxy) It is very simpe to 
configure and rock solid. So you can make perdition listen on 110, 
dovecotA listens on 111 and dovecotB listens on 112. A text file tells 
who is on which server. With this setup you can even migrate into the 
same directory from mbox to maildir.

> Any one else tryed such a thing?
>
> Cheers to all,
>
> luciano.

cheers,
dirk