For Los Alamos, blades offer a less costly and more reliable way of handling massive, parallel processing-based computations, such as simulations of galaxy formations and supernova explosions. "In general, it’s a more efficient solution with respect to space and energy consumption," says Wu-chun Feng, leader of the laboratory’s Research and Development in Advanced Network Technology (Radiant) team.

As blades slice into the IT mainstream, the technology may mark an important new stage in server evolution, one that will save space, boost reliability, streamline management and, ultimately, cut costs. Vendors are also hoping that blades will breathe fresh air into a dismal server market. Proprietary technologies, a nagging storage integration problem and old-fashioned vendor hype, however, all threaten to dull blades’ appeal.

Blades and Razors

A blade resembles an ordinary PC add-in card. In this case, however, the card is the computer. A typical blade features one or two processors, memory, storage?everything you would find inside a typical standalone server, minus the power supply, fan, network cables and other standard support components.

Individual blades sit inside a rack-mountable enclosure (sometimes called a razor). Those enclosures provide the blades’ support apparatus, such as I/O and power. A blade enclosure is usually called a U, which stands for a unit of vertical rack space?approximately 1.75 inches. Vendors generally discuss blade density in terms of the number of blades that can fit inside a standard 19-inch-wide 42U rack.

By sharing a common high-speed bus and U-mounted support components, blades achieve a degree of efficiency in size and power that standalone servers can’t match. Shrinking a server to the size of an add-in card permits impressive densities. Woodlands, Texas-based blade-maker RLX Technologies, for example, can wedge 24 blades in a 3U, which adds up to 336 independent servers in a single 42U rack with as much as 40 terabytes of storage and 336GB of memory.

Blades also let enterprises take advantage of the efficiency and reliability of clustered technology. Like most cluster-based systems, blade servers can be configured to include load-balancing and failover capabilities. Individual blades are usually hot-pluggable, which makes it easy to swap out a board with a new one in the event of system failure. Additionally, placing servers near each other and managing them under a single application can streamline administration.