What’s the true cost of helium disk drives?

The IT industry talks the talk on green computing, but talk is cheap. New helium disk drives promise better capacity, but at what environmental cost?

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While the IT industry has paid lip service to the idea of "green computing," the truth is that there is nothing environmentally friendly about technology. From the toxic substances used in the hardware to the vast amounts of power consumed by data centers, the only thing that is ever truly green is the color of the money we spend, at least in the US.

The public cloud changes things a bit, in the same way that electric cars change things. Electric cars still cause pollution; it's just that the pollution is centralized to where power is generated, and there is less of it per car because of the economies of scale. Public clouds still consume vast amounts of power, but that power is increasingly from places with capacity to generate it cheaply. There is also the economy of scale, too, which forms the basis for all things public cloud.

Full of hot air

Technology certainly drives some improvements that benefit the environment.  But it's hard to reconcile. And the latest disk drives from HGST/Western Digital have brought these ideas to the forefront of my mind. Their new 6 terabyte disk drives are filled with helium, instead of traditional air. That sounds interesting, until you think about the nature of helium.

The air inside a drive is a problem for manufacturers. It's a mix of gases, its density changes, and it holds heat and moisture and causes friction with the moving parts. In turn, the drives need larger motors, which consume more power and generate more heat. These factors also affect how close the platters in a drive can be, which directly affects storage capacity and density.

Helium is obviously a much lighter gas, and is considerably less dense, so HGST can produce a drive with 50% more capacity than anything else using 23% less power at idle. Helium is also inert, so it won't react with the metals inside the drive. Nor will it catch fire, like hydrogen. (Hydrogen would perform better inside a drive because it's even lighter, so long as you didn't mind your array blowing up from time to time.)

Helium is abundant, but it's too light to stay in Earth's atmosphere, and it isn't cost-effective to make helium. Our helium comes from radioactive decay inside the Earth's crust. Over millions of years that helium floats up through the Earth and gets trapped in the same pockets as natural gas. It's also harvested in much the same way. We owe our latest innovation in storage technology to the same folks that are in the news for hydraulic fracturing, or "fracking" —arguably not the greenest of energy sources.

At the same time, IT is competing with medical and scientific uses for helium. As an example, many of the high-technology medical scanners need to be cooled with liquid helium. I can't help but think about which I'd rather not have: A party balloon, twice as many movies on disk, or cancer.

In IT we're all innately used to tradeoffs, but perhaps we don't realize what we are trading. Are we trading disk capacity and cost for the ability to cure cancers or do science research? Are we trading disk capacity for clean, nonflammable water in communities around the world? There's a saying among storage people that the best I/O is the one you didn't have to do. Perhaps that is also the key to green computing: Less IT, in all regards, is truly more.

This was first published in January 2014

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