[Dovecot] mbox vs. maildir storage block waste

[Daniel Parthey]

Christoph Anton Mitterer wrote:
> On Wed, 2012-11-07 at 17:30 +0200, Timo Sirainen wrote:
> > On 30.10.2012, at 2.16, Christoph Anton Mitterer wrote:
> > > Have you ever thought about adding a "real" DB backend? Nothing against
> > > dbox... :) ... and I have no performance comparison of dbox with what
> > > could be done with a DBMS... but the advantage of the later would be
> > > that you get all fancy features from database systems for free... like
> > > fast indexing, online replication, etc. p..
> > > One might even reuse something like AOX for this.
> 
> > SQL indexes aren't very helpful for IMAP-like data. It would be fun to
> > some day have SQL backend in Dovecot (there already is read-only
> > INBOX-only SQL backend), but I don't expect it to have very good
> > performance.
> I see... well I haven't tested AOX or dbmail so far (especially as
> they're not in Debian and I was too lazy till now to compile them)...

Bad performance experiences with dbmail 2.x were the main reason why
we migrated to dovecot. If you've got a MySQL database with 80 GB of
binary chunks then things are getting ugly, especially when it comes to
efficient backup and restore of whole mailboxes or single e-mails.
The SQL backend (and the IMAP user experience) becomes very slow
if the database does not fit completely into RAM.

There are many performance improvements and bug fixes in dbmail 3.x,
but instead of evaluating then, we decided to migrate to Dovecot.

One should think twice, or even three times about how to design an
efficient SQL backend for a good user experience.

Regards
Daniel
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