According to the Maynard, Mass.-based company's Web site, customers' servers are available 99.9995 percent of the time, based on service incidents among more than 300 systems at customer sites. The sample includes more than 80 percent of the systems Stratus has sold. The servers that weren't included are ones that are still being installed and tested and have yet to become fully operational, the company said.
Stratus' server figures are the latest to come out of a competition between companies such as Sun Microsystems, Microsoft and Hewlett-Packard to achieve "five-nines" reliability--servers that workof the time, or spend less than 5 minutes per year on the blink. Different companies have laid claim to the coveted five nines over the years. But one company's results are often disputed by another company, owing to factors such as which software is running on the tested servers.
Stratus' figures may be more concrete than some offered up during the course of the "five-nines" race, but there's still wiggle room. For example, Stratus' claims don't include planned downtime, and Stratus' Windows servers have to be shut down to deal with software updates to address problems such as theworm.
Stratus debuted its line of computers--two-processor and four-processor machines that run Microsoft Windows--in 2001.
The ftServers are so named because of their "fault-tolerant" design, which uses "redundant" hardware components such as backup processors that take over if the main unit fails. Stratus also uses "hardened" software that's written more carefully to avoid crash-inducing situations. At the recentconference, Microsoft Chairman Bill Gates lauded the company's efforts in this area.
NEC developed the two-processor model and also sells Stratus machines through a.