[Dovecot] Maildirs location migration

[Timo Sirainen]

On Wed, 2013-04-10 at 18:59 +0200, Thomas Hummel wrote:
> On Wed, Apr 10, 2013 at 06:28:47PM +0200, Thomas Hummel wrote:
> 
> > So basically, it works as with conventional data moved with rsync in 2 phases
> > (initial copy and sync of the (hopefully small) reminder to minimize «downtime»
> > or incomplete state except that dsync is used to have the mailbox format and
> > dovecot knowledge, right ?
> 
> Isn't there still a critical section : new imap connections could be created
> (if auth is not denied temporary for this user) while the final sync still to
> be finished or started ?

Not if you kick the users out at the correct time:

 - dsync
 - switch user to new format
 - kick users
 - final dsync

It doesn't matter if new connections arrive during the final dsync,
because they are using the new format already. dsync merges changes, it
doesn't destroy any changes.