IBM turns server sideways for Web 2.0 apps

IDG News Service - SAN FRANCISCO -- IBM today unveiled a new type of rack-mount server designed specifically for companies running heavily trafficked Web 2.0 sites such as Facebook and MySpace. IBM announced the server at the O'Reilly Web 2.0 Expo here.

The server, called iDataPlex, was built to compete with unbranded so-called white-box PCs that online companies link together by the thousands to run busy Web sites. IBM said the new Linux-based server is based on Intel Corp.'s quad-core Xeon processors.

The company claims that the system consumes 40% less power while offering more performance than a typical rack-mount system. The energy savings come mostly from a new design that requires less power for cooling, IBM said.

Rack-mount servers are slender machines shaped like an oblong pizza box that are stacked on top of each other in server chassis. The servers come in standard heights -- 1u or 2u -- but their depth has been expanding as vendors try to cram in more hardware components.

Longer servers require additional cooling, since the server's fans blow air from back to front. "The power used by the fan is proportional to the cube of the fan speed, so if you want to double the fan speed you have to use eight times the power," said Gregg McKnight, chief technology officer of IBM's modular systems group.

IBM's answer is to rotate the server horizontally through 90 degrees, producing a server that is wider than usual but only 15 inches deep, compared to about 25 inches for a typical rack server. "That allowed us to run fans at a much lower velocity, and therefore save about 67% on the fan energy alone," he said.

IBM also pushed two racks together, creating a single wide rack that holds 84 iDataPlex servers. That allowed it to share three power whips between the servers, while two separate racks would normally use four. Power whips, the moveable outlets attached to power cables, cost $1,500 to $2,000 per month to maintain, McKnight said.

The broad surface area at the back also allowed IBM to design an optional water-cooled rear-door heat exchanger, which IBM said extracts all of the heat from the system so it doesn't contribute to data center warming.

The trade-off for sharing power cables is a less fault-tolerant system, but the software used to run busy Web sites is usually designed to fail over quickly to another server. "We interviewed Web 2.0 companies and they told us unanimously that they are designing their applications to tolerate server failures. So because it's more economical and more energy efficient, it's an attractive trade-off for them," McKnight said.