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Performance Computing: Load Balancing with DNS

Nov 07, 1999, 16:26 (0 Talkback[s])
(Other stories by William LeFebvre)

"A Web site's success can be measured by the amount of its traffic. Designers hope people will return and their audience will grow. But this form of success can also be a site's downfall. As traffic increases, two issues become vitally important to those running the site: redundancy and scalability. Both problems can usually be addressed by the same solution: more machines. But once a site grows from one server to five, how can the load be distributed among them?"

"Load balancing is a growing concern for any service that experiences high demand. It is especially important to Web sites, not only because of the nature of traffic growth, but also because of the unusual behavior of the HTTP protocol. The problem of redundancy and automatic recovery from failure is closely intertwined with load balancing, as a good load-balancing scheme will be able to work around detected failures."

"One way to attempt load balancing is to manipulate responses to Domain Name System (DNS) queries. Clients that want to access a Web site need to find an IP address for it first, and by altering responses to the DNS query for this address, we can get clients to hit different servers."

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