Western Digital Adds Something New to Hard Drives: Helium
When you think about it, aside from the fact that, over time, they increase in capacity while getting cheaper, there’s not that much new about hard drives. They store our digital stuff, occasionally give out, and that’s pretty much that.
But today, Western Digital is going to announce something a little different and interesting in the world of enterprise hard drives, and you should probably pay attention to it. Starting today, it will begin shipping hard drives packed with helium — as in the inert gas that makes balloons float, makes people’s voices sound funny, and which happens to be the second-most-abundant element in the known universe, after hydrogen.
It turns out that the insides of hard drives are pretty violent places. There’s a lot of high-speed motion, what with the disk platters spinning at several thousand rotations per minute, and the head moving back and forth across its surface. If you’ve ever held your arm out the window of a fast-moving car, you get some sense of the problem.
All that drag from the air limits the number of disk platters that can be stacked inside a single drive. Right now, the standard calls for five platters inside a one-inch-high drive enclosure. Building a sealed drive that’s packed with helium eliminates that drag, and thus allowed for platters to be packed inside the enclosure more tightly. Where you once could fit only five platters, you can now fit seven. That means more storage capacity per drive. The first drive out of the chute has a capacity of six terabytes, versus four for conventional drives.
It also means a little less power consumption overall, the company says. Less drag means that the motor spinning the platters has to turn less, and the drive runs a little cooler, meaning there’s fewer costs associated with that. They’re also a little quieter.
And, while getting just two more terabytes per drive doesn’t seem like much at first, when you multiply it out at scale, all sorts of things begin to add up. Deploying 11 petabytes of storage using current drive technology requires 12 racks and 2,880 hard drives, and about 33 kilowatts of power to run them. With the new helium-based technology, you could do it with eight racks and 1,920 individual drives, and run them on 14 kilowatts. The setup would take up less space, and require fewer cables, too.
A handful of big consumers of hard drives that are trying out the helium enhancement will be named in a Western Digital press release that’s set to go out later today: Hewlett-Packard is qualifying them for use in its servers. Netflix is trying them out in its movie-streaming infrastructure. Huawei, the Chinese networking and IT gear maker, is trying them out. CERN — the European Organization for Nuclear Research, a.k.a. the birthplace of the Web — is also trying them out.
Mike Cordano, HGST’s president, told me that the primary application everyone is talking about is cold storage. This is that “write once, retrieve occasionally” model of long time storage that is proving to be a fundamentally tricky prospect for companies like Facebook. The problem there is around old Facebook photos. They have to be stored, but even if you only look at them once a year or less, they still have to be accessible. It used to be that old data that is rarely used was stored on tape — not an option in the Facebook era. And scores of other companies face similar problems.
The secret sauce to all this is that the drives are built to be hermetically sealed, which means they’re both perfectly airtight and leakproof. While the science behind doing all this has been well understood for a while, Cordan says that Western Digital is the first to figure how to do it in a repeatable manufacturing process. It adds an extra step or two to the manufacturing process, and thus some cost.
It gets more interesting: Hermetically sealed drives don’t let the helium out, but they also don’t let anything else in, including liquid. That makes them good for use in immersion-cooled data centers. These are small, dense collections of IT gear packed into a box the size of a shipping container and filled to the top with nonconductive liquid that keeps everything running at a constant temperature. (If you didn’t know that this was a thing, you’re not alone, because I didn’t, either.)
Not that much helium is involved. A standard tank provides enough to build 10,000. And there’s a plentiful supply. There has been a recurring shortage of helium, going back a few a years, stemming from the way it’s distributed. Did you know for instance, that the U.S. Federal Government — specifically the U.S. Bureau of Land Management — runs a stockpile of helium that accounts for about a third of the world’s supply? Weird, right?