On 15/12/2010, at 7:00 PM, Victor Duchovni wrote: > On Wed, Dec 15, 2010 at 05:36:19PM +1100, James Gray wrote: > >> At the risk of being blacklisted on this rather "robust" forum, >> when I've needed a DB backend for mail I've invariably ended up >> with a product designed for that purpose. The idea of piping or >> scripting may seem desirable at first, but as mail volume increases >> the overhead becomes unmanageable > > The problem is not Postfix, rather when your mailstore is a custom > database, at high loads (O(100) msgs/sec per host) you need some > performant way to inject mail into said database, forking a database > client for each message is not a good option, so the DB mailstore needs > to present an LMTP (i.e. standard and in this case the right standard > interface is LMTP) injection service. > > So if you need a DB mail-store, and you need performance, insist on > LMTP support so you don't get locked into an unfortunate choice of > front-end MTA. > > If the DB mail product supports SMTP instead, that's fine too, but > LMTP is more appropriate for a non-queueing mail store, otherwise > you have to manage the complexity of yet another queue between > in front of the mailstore.
Indeed. DB mail has been a suitable solution for me in the past, but as you point out, it still needs an MTA (Postfix et al). However, DB mail also provides an LMTP interface. From the DB mail front page: "DBMail is made up of several components. A normal MTA (Postfix, SendMail, QMail, Exim) is used for accepting messages. The MTA hands the messages over to dbmail-deliver, using a pipe interface, or to dbmail-lmtpd, using LMTP (Local Mail Transport Protocol)." I've used it with an Exim front end and MySQL backend using dbmail-lmtpd with great success under very high mail volumes (think ISP with 40,000+ messages/minute peak). As always, the performance of a system is largely determined by its slowest component(s). Cheers, James
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