From owner-freebsd-isp Wed Aug 11 11:56:32 1999 Delivered-To: freebsd-isp@freebsd.org Received: from phoenix.aye.net (phoenix.aye.net [206.185.8.134]) by hub.freebsd.org (Postfix) with SMTP id 9782215585 for ; Wed, 11 Aug 1999 11:56:28 -0700 (PDT) (envelope-from barrett@phoenix.aye.net) Received: (qmail 5946 invoked by uid 1000); 11 Aug 1999 18:49:25 -0000 Received: from localhost (sendmail-bs@127.0.0.1) by localhost with SMTP; 11 Aug 1999 18:49:25 -0000 Date: Wed, 11 Aug 1999 14:49:25 -0400 (EDT) From: Barrett Richardson To: Stuart Henderson Cc: Chris Shenton , Steve Hovey , Mitch Vincent , freebsd-isp@FreeBSD.ORG Subject: Re: Loadbalance webservers In-Reply-To: <37B197BF.97C095B0@eclipse.net.uk> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-isp@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Wed, 11 Aug 1999, Stuart Henderson wrote: > > So the multiple records are a bit of a hack > > Yep, > > > and will hose you if one of the servers dies. > > Not really - most web browsers, proxies and telnets cycle through until > they find one that answers. Round robin DNS is in common enough usage that > it is quite well supported by client software. (Also, bind will randomise > the order and puts local networks first). > > > It would be way cool to modify the server-based daemon to have it > > determine the network distance/cost to the *client* then feed that to > > the lbnamed so it could return a record corresponding to the server > > fastest/closest to the actual client. This would implement WAN load > > balancing much like F5 Lab's $27K (each) 3DNS. > > I think Netscape used to do this in software (at least I always used > to get the IP address of their UK mirror returned) but they seem not to > be doing that now. > > Stuart > Could be an artifact of normal BIND behaviour. When a nameserver queries for something in somedomain.com it is given a list of randomly ordered NS records to try for a zone. The RTT to each of the nameservers is measured and queries are sent to the server that replies the quickest. The tracking of RTTs is done continually to account for any significant changes in the routes between the server that is asking and the server that is answering. - Barrett To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message