Success Stories

Powering the Search for Extraterrestrial Intelligence

Servers equipped with Quad-Core and Dual-Core Intel® Xeon® processors and running Red Hat Linux help the Search for Extraterrestrial Intelligence (SETI) program support a rapidly growing network of volunteers that scans the skies for signs of extraterrestrial life

Are we alone in the universe? Scientists agree that one of the best ways to answer that question is to look for evidence of extraterrestrial technology in the form of radio signals. To scan the sky for those signals, SETI uses the world’s largest single-dish radio telescope, located at the Arecibo Observatory in Puerto Rico. Every year the 1,000-foot diameter dish collects one petabyte (one petabyte equals one quadrillion bytes) of data, an amount so large that it is impractical for technicians to send it over the Internet. Instead, they place each day’s data on disk drives and ship them to SETI headquarters in California.

At the receiving end, scientists place the data in storage and begin processing it on 20 servers operated by SETI at the University of California, Berkeley. Those servers are used to divide up the data and distribute it in work-sized units to participants in the SETI@home program: more than 5 million people in 226 countries who have volunteered time on their PCs, workstations, and servers to help analyze the data for promising radio signals. Together, SETI volunteers constitute the world’s largest supercomputer, and the servers in Berkeley manage all of that computing power.

“With the Intel® Xeon® processors providing eight cores per server, we’re now able to process much more data in a shorter period of time.”
—Dan Werthimer, Chief Scientist, SETI@home, and Director, Center for Astronomy Signal Processing, University of California, Berkeley

Assessing the Situation
The SETI@home program has been growing rapidly. “Over 1,000 new people a day sign up to become volunteers,” says Dan Werthimer, chief scientist for SETI@home and director of the Center for Astronomy Signal Processing at UC Berkeley. “Not only are there more participants, but they’re also upgrading to more powerful systems. It all adds up to more demand on our servers here at Berkeley.”

The sheer volume of data involved is daunting. As a group, SETI volunteers can perform about 200 trillion floating point calculations per second. “If we just had one computer it would take us 2,000 years to do what the volunteers do in one day,” says Werthimer. “It’s the largest computation that has ever taken place on the planet. Our goal is to feed that computing capacity with enough data so that all our volunteers are working as much as they want.” Arecibo generates more than enough raw data to keep volunteers busy. The challenge is delivering it to them in usable form and administering the program to the exacting standards required in scientific work. “We take the data and break it up into small units so that everyone gets a different piece of the sky or a different part of the frequency band to analyze,” explains Werthimer. “That process is very compute-intensive, and it’s driven by over a million people a day requesting new data to work on. Our servers also perform a sophisticated final analysis of the results that volunteers send in.”

Meticulous record-keeping is essential. “Every work unit has to be tagged with the volunteer’s name and placed in our database record,” says Werthimer. “If we discover intelligent life, we’ll need to know who worked on the unit where it was found so they can share in the acclaim—and maybe a Nobel Prize.”

All of these demands stretched SETI’s servers to the limit, and by 2006 a large backlog of work had developed. “The growth of the program outstripped our capabilities,” says Werthimer. “Raw data was coming in and accumulating, yet we had volunteers waiting for work to do. It was simply that our servers couldn’t process the data and distribute the work units fast enough.”

Spotlight on SETI
Endorsed by the worldwide scientific community, the Search for Extraterrestrial Intelligence (SETI) is an organized effort to detect signs of extraterrestrial life. SETI scientists use the world’s largest radio telescope to search the universe for distant radio transmissions, and more than 5 million people around the globe volunteer time on their computers to analyze the search data.

Delivering the Solution
The SETI team decided to evaluate ways in which migrating to Intel® architecture-based servers could help solve the problem. “SETI has broad support among members of the scientific and high technology community,” says Werthimer. “Intel became aware of our needs and offered to help us make an assessment. Our evaluation showed that upgrading our aging, proprietary servers would be difficult and costly. But with rack-mounted servers using Intel® processors, we could accommodate growth by adding a few units at a time as needed.”

Intel engineers recommended multi-core processors to boost server performance. SETI had little budget available, so Intel representatives came up with an innovative way to help provide new infrastructure. They arranged for SETI to receive ongoing donations of Intel “white box” servers—unbranded units that are built to demonstrate the latest Intel® platforms and become available after they are used in new product introductions. “The donated white box servers enable us to get the newest Intel server technology just months after it is introduced to the market,” says Werthimer. “Since we operate on a small grant, we’re very grateful to companies like Intel who are willing to help us out.”

“Looking ahead, we’re very excited about Intel’s 45-nanometer manufacturing process that further shrinks transistors and power consumption, yet also boosts speed. That means we can continue to put more processing power into the limited space we have available.”
—Dan Werthimer, Chief Scientist, SETI@home, and Director, Center for Astronomy Signal Processing, University of California, Berkeley

Boosting performance while holding down costs
Using four-way servers equipped with the Dual-Core Intel® Xeon® processor 7000 sequence, the SETI team was able to increase responsiveness, speed, and multitasking compared to the old servers. “With the Intel Xeon processors providing eight cores per server, we’re now able to process much more data in a shorter period of time,” explains Werthimer. “We estimate we have increased our processing capabilities by at least a factor of two.”

Werthimer’s team was pleased to discover that no additional data center space or air conditioning was needed. “Even though the new servers deliver more processing power, they fit in less space than our previous machines,” he says. “They’re also a lot more energy efficient and don’t generate as much heat. That’s important to an organization like ours that doesn’t have the extra budget to rent more space or handle a big jump in power and cooling costs.”

“Even though the new servers deliver more processing power, they fit in less space than our previous machines.They’re also a lot more energy efficient and don’t generate as much heat. That’s important to an organization like ours that doesn’t have the extra budget to rent more space or handle a big jump in power and cooling costs.”
—Dan Werthimer, Chief Scientist, SETI@home, and Director, Center for Astronomy Signal Processing, University of California, Berkeley

Eliminating the data processing backlog
Since the organization switched to servers with the Dual-Core Intel Xeon processor 7000 sequence, the SETI team has not only kept up with incoming data, but is also making headway on analyzing the backlogged data. Another performance boost is expected with the arrival of white box servers using quad-core Intel® processor technology. “As we gradually replace our original servers with new ones using dual-core and quad-core processors, we will completely eliminate the data analysis bottleneck,” Werthimer says. “It’s working beautifully for us.”

In addition to more processing power, the new Intel® Xeon® processors have a sizeable data cache that is very important for SETI. “A lot of our processing uses the Fast Fourier Transform or FFT algorithm, which is heavily dependent on memory access,” says Werthimer. “The added cache is a big plus, helping us do even more work in less time.” In 2008, SETI will be adding servers with Intel processors based on 45-nanometer technology. “Looking ahead, we’re very excited about Intel’s 45-nanometer manufacturing process that further shrinks transistors and power consumption, yet also boosts speed,” adds Werthimer. “That means we can continue to put more processing power into the limited data center space we have available.”

The new Intel processor-based servers will be put to good use, because SETI’s processing needs are about to take a quantum leap. The team will soon begin using a new method, called Astropulse, to search for bursts of radio waves that might come from extraterrestrial civilizations or from new types of objects in space that scientists haven’t discovered yet. “Astropulse is very exciting, but it takes a lot of computing power,” says Werthimer. “Thanks to our volunteers, we have the biggest supercomputer on the planet, about 90 percent of it equipped with Intel processors. Now we just need more Intel technology-based servers to manage it.”

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