[Dovecot] converting from mbox to maildir ?

[Timo Sirainen]

On Thu, 2012-02-02 at 09:53 +0100, Frank Bonnet wrote:
> Le 02/01/2012 09:39 PM, Timo Sirainen a écrit :
> > On 30.1.2012, at 10.37, Frank Bonnet wrote:
> >
> >> We are planning to convert our mailhub ( freebsd 7.4 ) from mbox
> >> format to maildir format.
> > I'd do it one user at a time with dsync, but unfortunately:
> >
> >> the machine use real users thru openldap ( pam_ldap + nss_ldap )
> > nss_ldap can't store the mail_location override field needed to distinguish mbox user from maildir user. Maybe you could temporarily switch to some other userdb, which would allow extra fields. Also this requires that you deliver mails using dovecot-lda/lmtp.
> >
> >> another problem is disk space. The users's email data takes about
> >> 2 Terabytes of data and I cannot duplicate as I only have 3 Tb on
> >> the raid array of the server.
> > With one-user-at-a-time conversion this wouldn't be an issue.
> >
> 
> so is there a massive conversion method ?

dsync works for that too:

1. dsync backup all users somewhere
2. wait close to the time you can shut down dovecot
3. dsync backup all users the second time
4. shutdown dovecot and MTA
5. dsync backup once more (hopefully this will be relatively quick)

The idea is that you can do incremental dsync backups. You'll of course
need to do this in a way that you don't run out of disk space..