Date: Wed, 13 Oct 2004 00:50:08 +0300 From: Vlad GALU <vladgalu@gmail.com> To: Stephane Bortzmeyer <bortzmeyer@nic.fr> Cc: freebsd-isp@freebsd.org Subject: Re: Documentation of big "mail systems"? Message-ID: <79722fad04101214505dd69738@mail.gmail.com> In-Reply-To: <20041012212051.5A91A148D1@mail.sources.org> References: <20041012212051.5A91A148D1@mail.sources.org>
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On Tue, 12 Oct 2004 23:20:51 +0200, Stephane Bortzmeyer <bortzmeyer@nic.fr> wrote: > I'm currently writing a proposal for a webmail service for, say, 50 > 000 to 500 000 users. I'm looking for description of existing "big > mail" systems, using technologies like scalemail > (http://scalemail.sourceforge.net/), specially with an emphasis on the > storage subsystem for the servers (my weak point, I don't really have > enough experience with SAN, NAS, and so on). > > Of course, with a FreeBSD (and free software) bias :-) > > I do not need general advice (such as "Postfix rules, Exim sucks" or > "Maildirs are faster") but actual description of existing and running > systems. Googling seems inefficient for that purpose and I presume > that many interesting papers are only in closed and paying conference > proceedings :-( > I've been running a system with ~2,500,000 e-mail accounts for about two years. It uses qmail and a specially crafted version of vpopmail. We modified vpopmail so it uses the sqlrelay API instead of the original one, so we could proxy all the database requests through a single connection. The Maildirs are stored on another machine, with fast fibrechannel disks. For POP/IMAP we use Courier-IMAP, which uses vpopmail as a storage backend. The system is perfectly scalable. Our number of users has known a very abrupt growth in the last 7-8 months, but it behaved really nice. Database machines can be indefinitely upgraded. Storage devices can be added. As a personal notice, disk I/O would be more efficient with Postfix, but we chose vpopmail's management flexibility instead. We extended its API and rewrote the information it kept about every account (some user prefs among other stuff). The relay machines use qmqp to relay mails in a round-robin fashion to four machines that act as outgoing default gateways, thus dramatically improving the performance on the storing machines. I can't see this going down in less than 7-8 years. P.S. the vpopmail backend is PostgreSQL. > _______________________________________________ > freebsd-isp@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-isp > To unsubscribe, send any mail to "freebsd-isp-unsubscribe@freebsd.org" > -- If it's there, and you can see it, it's real. If it's not there, and you can see it, it's virtual. If it's there, and you can't see it, it's transparent. If it's not there, and you can't see it, you erased it.
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