From owner-freebsd-isp@FreeBSD.ORG Fri Jul 7 12:18:52 2006 Return-Path: X-Original-To: freebsd-isp@freebsd.org Delivered-To: freebsd-isp@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8A23116A4DE for ; Fri, 7 Jul 2006 12:18:52 +0000 (UTC) (envelope-from b.candler@pobox.com) Received: from proof.pobox.com (proof.pobox.com [207.106.133.28]) by mx1.FreeBSD.org (Postfix) with ESMTP id E75BE43D73 for ; Fri, 7 Jul 2006 12:18:51 +0000 (GMT) (envelope-from b.candler@pobox.com) Received: from proof (localhost [127.0.0.1]) by proof.pobox.com (Postfix) with ESMTP id C50F52A312; Fri, 7 Jul 2006 08:18:50 -0400 (EDT) Received: from mappit.local.linnet.org (212-74-113-67.static.dsl.as9105.com [212.74.113.67]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by proof.sasl.smtp.pobox.com (Postfix) with ESMTP id 716CB62558; Fri, 7 Jul 2006 08:18:48 -0400 (EDT) Received: from lists by mappit.local.linnet.org with local (Exim 4.61 (FreeBSD)) (envelope-from ) id 1FypIF-0009QO-0L; Fri, 07 Jul 2006 13:18:47 +0100 Date: Fri, 7 Jul 2006 13:18:46 +0100 From: Brian Candler To: User Freebsd Message-ID: <20060707121846.GA36201@uk.tiscali.com> References: <20060706235712.A1171@ganymede.hub.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060706235712.A1171@ganymede.hub.org> User-Agent: Mutt/1.4.2.1i Cc: FreeBSD ISP , Francisco Reyes Subject: Re: IAMP servers in FreeBSD for ISP X-BeenThere: freebsd-isp@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Internet Services Providers List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 07 Jul 2006 12:18:52 -0000 On Fri, Jul 07, 2006 at 12:00:17AM -0300, User Freebsd wrote: > >Anyone care to share what IMAP servers they have found to scale best? > > By far, IMHO, the best is cyrus-imapd ... it was originally developed by > Carnegie-Mellon University to handle their on campus email, and grew > quickly out of that ... > > If I recall your environment at all, one nice feature of it is that it > supports something called MURDER, which, effectively, is a way of having > your mailboxes literally spread out over multiple backend servers ... > all the mail comes in through ServerA, but, as an example, mailboxes a-m > get stored on ServerB, and n-z go to ServerC ... > > They've also just recently added a replication ability, so that you can > have backup servers ... ServerD is a backup of ServerB, ServerE is a > backup of ServerC ... > > The thing is, it would most likely eliminate, or greatly reduce, your NFS > requirements ... Conversely, it also means that it is not safe to use with NFS backends. So if you already have a good and/or expensive NFS appliance, you won't want to use Cyrus. Remember that Courier has a proxy front-end built in, so you can use a proxy cluster instead of an NFS cluster (or even have some accounts on Courier and proxy others to Cyrus; a very nice migration tool) If you do want to go the Cyrus route, there are some good papers from Cambridge University in the UK describing their setup: http://www-uxsup.csx.cam.ac.uk/~fanf2/hermes/doc/talks/2004-02-ukuug/ http://www-uxsup.csx.cam.ac.uk/~fanf2/hermes/doc/talks/2005-02-eximconf/ Actually I have very good experience of courier-imap + exim in a large ISP environment, but the vast majority of users were POP3, not IMAP. Also, although Courier's sqwebmail has a not particularly pretty interface, it *does* perform very well under heavy usage (I suspect much better than a PHP->IMAP solution) since it accesses the Maildirs directly. Regards, Brian.