From owner-freebsd-chat Fri Feb 14 10:14:52 2003 Delivered-To: freebsd-chat@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id C6CB637B401 for ; Fri, 14 Feb 2003 10:14:50 -0800 (PST) Received: from wolfbert.skynet.be (wolfbert.skynet.be [195.238.3.13]) by mx1.FreeBSD.org (Postfix) with ESMTP id 9EB2743FBD for ; Fri, 14 Feb 2003 10:14:47 -0800 (PST) (envelope-from brad.knowles@skynet.be) Received: from picard.skynet.be (picard.skynet.be [195.238.3.88]) by wolfbert.skynet.be (8.12.7/8.12.7/Skynet-OUT-FALLBACK-2.22) with ESMTP id h1EER7Zr020786 for ; Fri, 14 Feb 2003 15:27:34 +0100 (MET) (envelope-from ) Received: from [10.0.1.2] (ip-26.shub-internet.org [194.78.144.26] (may be forged)) by picard.skynet.be (8.12.7/8.12.7/Skynet-OUT-2.21) with ESMTP id h1EEQlHp020920; Fri, 14 Feb 2003 15:26:56 +0100 (MET) (envelope-from ) Mime-Version: 1.0 X-Sender: bs663385@pop.skynet.be Message-Id: In-Reply-To: <3E4C9612.2777D62E@mindspring.com> References: <20030211032932.GA1253@papagena.rockefeller.edu> <3E498175.295FC389@mindspring.com> <3E49C434.D8D497EE@mindspring.com> <3E4A83BC.8A15E7C3@mindspring.com> <3E4B12F5.2608BBB@mindspring.com> <3E4BB64E.A9AEED28@mindspring.com> <3E4C9612.2777D62E@mindspring.com> Date: Fri, 14 Feb 2003 14:03:47 +0100 To: Terry Lambert From: Brad Knowles Subject: Re: Email push and pull (was Re: matthew dillon) Cc: Brad Knowles , Rahul Siddharthan , freebsd-chat@freebsd.org Content-Type: text/plain; charset="us-ascii" ; format="flowed" Sender: owner-freebsd-chat@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org At 11:09 PM -0800 2003/02/13, Terry Lambert wrote: > No... but does proxy really solve anything, then, more than > a DNS rotor solves? All it really does is add a single point > of failure. Unless you can target a subset of back end content > servers, you might as well use DNS round-robin. Using a proxy > implies the back end replica problem is *already* solved. Yes, the proxy does solve the domain problem. The user logs in with "user@domain", the proxy looks this up in the LDAP database, which then tells it which back-end server to contact. You can decide, on a user-by-user basis, which back-end server they will be using for their mail. If one back-end server gets overloaded, you can choose individual users to shift off to another machine. Besides, you don't use just one front-end proxy. You use them in sets of at least two, and you drop L3/L4 load balancing switches in front of them, and the L3/L4 switches get DNS round-robin. The switches handle balancing the connection load, and the proxy+database handles the balancing of user mailboxes over the set of potentially asymmetric back-end servers. The issue of replication is a totally different matter. > Maybe I should say "doesn't deal with LDAP the way it should" > instead? In what way? -- Brad Knowles, "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." -Benjamin Franklin, Historical Review of Pennsylvania. GCS/IT d+(-) s:+(++)>: a C++(+++)$ UMBSHI++++$ P+>++ L+ !E-(---) W+++(--) N+ !w--- O- M++ V PS++(+++) PE- Y+(++) PGP>+++ t+(+++) 5++(+++) X++(+++) R+(+++) tv+(+++) b+(++++) DI+(++++) D+(++) G+(++++) e++>++++ h--- r---(+++)* z(+++) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message