The key to incorporating far-flung, intermittently available data centers into a cloud infrastructure, says Ripduman Sohan, a postdoctoral fellow who worked on the paper, is to be choosy about which processes are offloaded to them.
“I think Facebook would not want to put forward-facing Web services onto an architecture like this, for various reasons,” says Sohan. However, a company like Facebook could offload projects that are not particularly time-sensitive but still sizable, such as processing analytics. “There are a bunch of batch-type jobs that could easily be offloaded to an architecture like this,” says Sohan.
At least one real-world implementation of a system similar to the one proposed by the Cambridge team already exists. Called the GreenStar Network, it connects data centers powered entirely by renewable energy in Canada, Spain, Ireland, and Iceland. So far, the challenges inherent in porting large amounts of data and live computing processes from one data center to another in near-real time have been significant but surmountable.
The network uses supervisor software to shift computing according to the availability of wind and solar power at various sites, and, says Martin Brooks, an independent research consultant working on the GreenStar Network, this works well enough to allow the network to handle even finicky applications like running a video server. The video, says Brooks, doesn’t skip even as the virtual machines hosting it are transferred, over an ultrafast fiber-optic network, between servers thousands of miles apart. “We have certainly had people consider [this project] outlandish, but we live it every day, so we don’t think that way,” he says.
Whether the Cambridge research will result in data centers in places as exotic as platforms in the middle of the Atlantic is anyone’s guess, says Hopper, who also admits that some of his visions for the project may be over the top. His colleague Sohan is less ambitious. “Sometimes when I talk to Hopper about this, I say that an easy way to bootstrap this project is to put a Sun modular data center in existing renewable energy sites.”
Sun already has a data center that fits in a single shipping container, notes Hopper. Getting one to a renewable energy plant is as simple as taking it there on a truck. Connecting it to the Internet, however, is another matter: the team’s models are based on the kind of high-speed fiber-optic networks that are available to academics but have yet to become economical for most commercial applications. Once they are, says Hopper, “we imagine putting photons into places that are godforsaken for every other reason except for generating energy.”