Technology Review: Netbook Chips Create a Low-Power Cloud
Using a cluster of the same processors that normally show up in netbooks and similar mobile devices, researchers have created a powerful server architecture that draws less power than a lightbulb.
The architecture, dubbed a 'fast array of wimpy nodes,' or FAWN, offers a way to decrease by an order of magnitude the amount of power used by the computational infrastructure of Internet giants like Google, Microsoft, Amazon, eBay, Facebook, and others. If the predictions of its inventors are borne out, it could have a significant impact on both the bottom line and the environmental impact of cloud computing.
Power now accounts for up to 50 percent of the cost of operating data centers, and in the United States, its cost per kilowatt-hour is increasing. Even relative newcomers like Facebook use up to $1 million a month in electricity, and the Environmental Protection Agency (EPA) projects that by 2011, data centers in the United States could use up to 100 billion kilowatt-hours of electricity, for a total annual cost of $7.4 billion, with an estimated emissions impact of 59 million metric tons of CO².
FAWN, which is described in an as-yet-unpublished paper by David Andersen and his team at Carnegie Mellon University, tackles this problem with a combination of relatively slow processors (the kind used in netbooks and other mobile devices) and flash memory (the kind that stores data in digital cameras and USB drives). The somewhat counterintuitive result is an architecture whose performance per watt of energy is a hundred times better than that of traditional servers, which use faster (but much more energy-hungry) processors and disk-based storage.
The exceptional performance of FAWN is limited to certain kinds of problems--random access of small bits of information--but this kind of input/output-intensive task is exactly what strains the existing infrastructure of Web companies like Facebook.
FAWN is composed of many individual nodes, each with a single 500-megahertz AMD Geode processor (the same chip used in the first One Laptop Per Child $100 laptop) with 256 megabytes of RAM and a single four-gigabyte compact flash card. The largest FAWN cluster built to date, consisting of 21 nodes, draws a maximum of 85 watts under real-world conditions.
Each FAWN node performs 364 queries per second per watt, which is a hundred times better than can be accomplished by a traditional disk-based system working on an input/output-intensive task, such as gathering all the disparate bits of information required to display a Facebook or FriendFeed page or a Google search result.