Rich Ptak of The Hurwitz Group says it is. Recent customer profiles published by IBM and others seem to suggest that the figure of 500 is actually somewhat conservative. Telia, a European telecomm company, replaced over 700 Sun machines with one zSeries recently. IBM's Pete McCaffrey, program director for Enterprise Server Marketing, concedes that the raw MIPS of a mainframe do not equal the raw MIPS of five hundred Sun servers. But he says it's real-world throughput, not published MIPS, that should be compared, and that segregation of total capacity onto hundreds of individual servers prevents the kind of dynamic load sharing that a single mainframe can do.
Utilization rates are often only twenty to thirty percent of capacity.
The mainframe takes advantage of the bursty nature of system load in e-commerce and web applications, just as a utility company takes advantage of load averaging among thousands of consumers, and thereby avoids the need for a system that can meet the peak demand of all of the Linux instances at the same time. In scientific applications, for example, you won't get the same equivalency. But he says that business deployments at customer sites are bearing out IBM's claims of zSeries benefits. An ASP hosting company that is adding twenty rack mount server per week, McCaffrey observes, rapidly becomes mired in bad economics. From The Matterhorn Group's Perspective The Matterhorn Group, based in New York, approached the question of mainframe economics somewhat differently but arrived at some of the same conclusions as The Hurwitz Group.