[Dovecot] Using MySQL to store email?

[Joshua Goodall]

Marc Perkel trolled:
> So Timo,
> 
> Have you considered the idea of storing all the email in a MySQL 
> database? Seems to me that MySQL could somplify all the backend stuff 
> that everyone struggles with and with replication one could create
very 
> massive and reliable systems. What would it take to use MySQL that
way?

Maybe we could recode Dovecot in PHP, too.

Sorry, that was nasty.  However, having recently experimented with a
very large mail storage system using mysql, I strongly advise against
this avenue.  In particular, the two main backends have serious
deficiencies when you get up to the multi-gigabyte ranges:

* MyISAM doesn't restart in constant time.
* InnoDB's next-key locking kills performance on large blob inserts &
deletes.

Anyway, what do you mean, everyone struggles with backends?  Dovecot's
backends are fast, modular and reliable.

Regarding replication; all good logical volume managers can do this.

Regarding massive; all good filesystems can do this.

Regarding reliable; I guarantee that mysql reliability (when properly
managed) is still lower than that of a filesystem (when properly
managed).

In fact, the whole argument is specious.  Filesystems already are
databases, optimised for storing arbitrary-sized data objects using a
hierarchical key, which is practically the definition of mail storage.

/jg