Providing fault tolerance as well as the ability to scale beyond the capacity of a single server, load balancers are practically a necessity for any commercial site. Because loads on a given Web site can fluctuate by several orders of magnitude (five or six, in the case of sites like Victoria's Secret or the World Cup Soccer site), and given that thousands of dollars a minute may be lost if the site is unavailable, being able to spread the load across many servers and ensure that users can still connect, even if one or more physical servers fails or stops responding, is crucial.

The latest load balancer available from Coyote Point Systems is the Equalizer E550si, a 1u (1.75"-high) appliance that offers 20 10/100/1000 ports, all the load-balancing features necessary to set up a sophisticated Web farm or other type of virtual cluster, and excellent performance, at a cost of $10,995 US.