Why the webscale world — and CERN — is stoked about helium-filled hard drives

Storage vendor HGST is now shipping 6-terabyte hard drive systems filled with helium, and the technology already has some very big fans. CERN is testing the drives on the 60-petabyte storage system where its scientists keep their active data, and companies such as Netflix, HP, and a few anonymous large social media and search companies are also putting the drives through their paces.

Why? Because the new drives — called the HGST Ultrastar He6 — promise to store more data in the same amount of physical space as standard hard drives, while also lasting longer and using less energy. These are critical concerns when you’re running thousands of hard drives and every added bit of density or every dollar saved on the power bill adds up.

It’s helium’s most obvious property — that it’s lighter than air — that makes it so ideal for high-capacity storage media. Disks can spin easier inside the drive, thus reducing vibrations between and arm and disk, and also cutting down on air friction, HGST Vice President of Marketing Brendan Collins said. Less vibration and less friction mean longer life and less power consumption. They also mean HGST can pack seven disks and 6 terabytes into the same 1-inch of drive space that traditionally includes 5 disks and 4 terabytes, without sacrificing the accuracy of reads and write due to excessive vibration.


HGST has been working on the helium technology for about 10 years, Collins explained. First, it needed to find a gas that was lighter than air, relatively cheap and wouldn’t react with the other components in the drive. That was actually easy enough — what was harder was optimizing all of those components to work with helium and then creating an automated assembly process for hermetically sealing the helium inside the drives. For several years, the eventual leakage of helium from the drives was a major limiting factor in the their usability, Collins noted.

Putting helium to the test at CERN

“So far everything is going fine,” CERN’s head of IT procurement Olof Barring told me regarding the agency’s tests on two of the helium-filled drives, noting that it’s awaiting a shipment of 24 more drives to conduct a more thorough test. “… We are very happy with the drive, actually.”

He wasn’t sure this would be the case because there was the possibility that the external vibrations emanating from the other gear in CERN’s high-performance data center environments would cause problems with the tightly packed disks within the helium drives. So far, though, that hasn’t been an issue. If the additional tests go well, and if HGST prices the drives right, helium-filled drives could become a big part of CERN’s storage infrastructure, Barring said.

For CERN, though, the biggest impact of helium drives could come down the road if their price per terabyte drops low enough and their lifespan continues increasing. Because while the agency is looking to add the HGST drives to its scientists’ production storage environment, CERN still has a huge tape archive and is throwing away the vast majority of the data its instruments generate.

“I think tape is still a very living technology,” Barring said. “… If it’s going to be replaced by disk, disk has to become more cost-efficient.”

Disk drives would also have to become more reliable. If a drive fails, CERN essentially loses that data — and tape is a lot more reliable in that regard. Perhaps, Barring noted, a disk drive system that had the benefits of helium but also turned off disks when they’re not being accessed could do the trick for large-scale archival.

“For the moment, I think, we don’t see an alternative to tape,” he said.

The economics of going with helium.
The economics of going with helium.

Although, he added, another bright spot of the helium-filled drives is that they make it easier to add capacity to the production storage system, meaning scientists don’t have to move their data off of it and onto tape drives too soon. This doesn’t mean they’ll get anywhere near capturing all of the 100 terabytes of data that stream off CERN’s instruments every second, but maybe they can get a little closer.

Right now, about 99 percent of that data is filtered away based on the scientists’ knowledge of what they need and what they don’t, “But I’m sure they would feel much safer if we could store everything,” Barring said.

Can helium spur innovation and fend off flash?

Outside of CERN’s extreme requirements, though, HGST and some of its partners are pretty excited about what the helium-filled drives could mean in more mainstream data centers. Because of their tight sealing, for example, the drives are especially suited for immersion oil cooling like what Green Revolution Cooling provides.

The new drives, with their improved capacity and energy efficiency, could also let HGST and parent company Western Digital fend off any advances that flash storage might make on the capacity storage industry, Collins said. Although flash is getting cheaper by the day, there’s still a big difference in price between it and spinning disks. “When we do helium,” he said, “that will allow us to stay on that curve and keep that gap just as big.”

Feature image courtesy of Shutterstock user kubais.