[Dovecot] migrating/converting from system users -> virtual users

[Timo Sirainen]

On 28.2.2012, at 19.45, Steve Platt wrote:

> Most of this is working but I'm stuck on how to convert users' mail folders 
> from the existing setup to the new one. I'm using the convert plugin but of 
> course the problem is that the plugin executes as the "vmail" user and cannot 
> access the existing mail folders that belong to the users: and I'd be worried 
> if it could, of course!

Convert plugin also has some other problems.

> I have the idea that I should be able to run some command (as a privileged 
> user) on the mail server and have it do the conversion for me, changing the 
> ownership/permissions on the way.
> 
> Can convert-tool do this?

Possibly, but I remember it had some problems. The best solution would be to use Dovecot v2.0's dsync. Also you can use one of the scripts in http://wiki2.dovecot.org/Migration/MailFormat such as mb2md.

> I'd prefer to go with the automatic (plugin) conversion if I can bodge the 
> ownership issues somehow. Failing that, some tool or script may be the next 
> best answer.

You could set mail_drop_priv_before_exec=yes, mail_access_groups=vmail and chgrp vmail, chmod g+rw the old mailboxes.