“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.“