"Five Nines"—Is it even Possible?

99.999% availability amounts to a mere five minutes of downtime per year, roughly the time it takes to reboot a single server. Fearful of not being considered in the same league with Hewlett-Packard, IBM, and Sun as a provider of high-availability mission-critical server products, Microsoft has launched an advertising campaign based on the “five-nines” availability concept. But five-nines availability is possible only if organizations are willing to make very large investments in the necessary technology, people, and processes, and even then few customers are managing to achieve the magic number. It also comes at the cost of “agility”—the subject of another Microsoft advertising campaign. The customer for whom five-nines availability is most important may be Microsoft itself—its own services do not yet meet that standard, but they must if it expects to be successful in providing Web services, such as the recently announced HailStorm project.

To claim five-nines availability, Microsoft must play loosely with the term—in the fine print Microsoft does not actually claim 99.999% availability, but rather that Windows 2000 Servers are “designed to deliver 99.999 percent server uptime.” However, an Aberdeen study of 10 existing production sites found that Windows 2000 servers are running at an average rate of only 99.964% uptime.