[Dovecot] Compressing existing maildirs

Dovecot-GDH
Wed, 28 Dec 2011 23:56:33 -0000

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.

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.

On Dec 24, 2011, at 7:20 AM, Jan-Frode Myklebust wrote:

> I've just enabled zlib for our users, and am looking at how to compress
> the existing files. The routine for doing this at
> http://wiki2.dovecot.org/Plugins/Zlib seems a bit complicated. What do
> you think about simply doing:
>
> 	find /var/vmail -type f -name "*,S=*" -mtime +1 -exec gzip -S Z
-6 '{}' +
>
>
> I.e. find all maildir-files:
>
> 	- with size in the name ("*,S=*")
> 	- modified before I enabled zlib plugin
> 	- compress them
> 	- add the Z suffix
> 	- keep timestamps (gzip does that by default)
>
>
> It's of course racy without the maildirlock, but are there any other
> problems with this approach ?
>
>
> -jf