[Dovecot] mbox vs. maildir storage block waste

[Timo Sirainen]

On 29.10.2012, at 23.54, Christoph Anton Mitterer wrote:

> On Mon, 2012-10-29 at 23:42 +0200, Timo Sirainen wrote:
>>> btw: What are the actual advantages of sdbox over maildir?
>> 
>> * Not moving files from new/ to cur/ directory
>> * Not renaming files when changing message flags
>> * Not readdir()ing directories (although maildir_very_dirty_syncs=yes helps a lot with this)
>> 
>> Basically less disk I/O and making it possible to have mailboxes with a huge number of messages without everything slowing down horribly.
> 
> Oh that's quite some advantage...
> 
> And I guess the interior of the files is the same? I.e. just the plain
> mail without any changes or quoting?

Yes, but it's in dbox format so it contains also some extra metadata (not in the mail headers).

> For sdbox, does that part with "loosing the indexes means game
> over" ;) , too?

You'll lost message flags then. Both sdbox and mdbox keep dovecot.index.backup files and repairing tries very hard to preserve everything from the indexes it sees, so I don't think it's a big concern as long as the system behaves properly.