[Dovecot] Compressing existing maildirs

Jan-Frode Myklebust
Thu, 29 Dec 2011 08:49:16 -0000

On Wed, Dec 28, 2011 at 03:56:33PM -0800, Dovecot-GDH
wrote:
> The cleanest (though not necessarily simplest) way to go about this would
be to use dsync to create a new maildir and incrementally direct traffic to a
separate Dovecot instance.
>
> Unless you have a legacy application that relies on maildir, switching to
mdbox would be a good idea too.

We just got rid of the legacy app that worked directly against the
maildirs, which is the reason we now can turn on compression. I
intend to switch to mdbox, but first I need to free up some disks by
compressing the existing maildirs (12 TB maildirs, should probably
compress down to less than half).

>
> I expect that with Dovecot compression is something that can "just be
turned on", but for fear of any possible issue, I chose to migrate
mailboxes in batches with the way mentioned above.
>

Migrating to mdbox is much scarier to me than an easily reversible
compression of existing maildir files.

Could you please give a bit more details about how you did this migration?
Did you change user home dirctory in the process? Seeing the scripts you
used to run the migration would be very interesting..


  -jf