[Dovecot] Migrating mbox to maildir

[Kenneth Porter]

On Thursday, August 14, 2008 3:46 PM -0400 Mike Hobbs <mhobbs at mtl.mit.edu> 
wrote:

> I'd like to use maildir with all my new users, but I'd like to be able to
> continue using mbox for my old users and slowly convert them as I get
> time.

I did this a week ago for about a dozen users and the system seems more 
responsive.

Timo covered the Dovecot side. You didn't say what delivery agent you're 
using. I use procmail and put this .procmailrc in the home directories of 
the converted users:

# deliver to Maildir
MAILDIR=$HOME/Maildir
DEFAULT=$MAILDIR/

The file should be owned by the user. (I forgot to chown the file for one 
user and mail was delivered to the old /var/spool/mail/user mbox file. 
After I figured it out, I did another conversion with convert-tool to a 
temporary Maildir-new and moved the converted inbox into a new folder under 
his previously-converted ~/Maildir.)

If a user is using procmail for filtering, he'll need to change the 
destination folder lines in his filters. This list could be filtered with a 
rule like this:

:0 :
* ^Sender:.*dovecot
$HOME/Maildir/.Lists.Mail.Dovecot/

Note the trailing slash on delivery lines to indicate that the destination 
is in Maildir format.

To avoid reconfiguring the folder separator on clients, you can add this 
namespace directive to dovecot.conf:

namespace private {
   separator = /
   inbox = yes
}