Flash Drives

Flash Drives Replace Disks at Amazon, Facebook, Dropbox

SAN JOSE, CALIFORNIA — If you drive south from San Jose until the buildings are few and far between, exit the highway, and take a quick left, you’ll find a data center occupied by some of the biggest names on the web. Run by a company called Equinix, the facility is a place where the likes of Google, Facebook, and Amazon can plug their machines straight into the big internet service providers.

If you’re allowed inside and you walk past the cages of servers and other hardware, you can’t see much. In most cages, the lights are off, and even when they’re on, there are few ways of knowing what gear belongs to what company. Some companies don’t want you to see. Google engineers have been known to wear miner helmets when installing new hardware, determined to keep their specialized gear hidden from the competition.

But if you walk into the right building and down the right aisle, you’ll run into a giant Dropbox logo. Clearly, the file-sharing upstart is proud of its data center gear. But at the same time, it doesn’t think this hardware is all that different from what the rest of the world is using. And that’s about right.

Inside its cage, Dropbox is running servers equipped with solid-state drives, also known as SSDs — super-fast storage devices that could one day replace traditional hard drives. The company doesn’t use SSDs in all its servers, but it’s moving in that direction. In other words, Dropbox is like the web as a whole. Such names as Facebook, Amazon, Microsoft, Mozilla, and Wikia are also using solid-state storage in their data centers, and judging from anecdotal evidence, the trend goes even further.

Like a hard drive, an SSD is a device for storing information. But unlike a hard drive, it doesn’t have any moving parts. Today’s SSD are built with flash memory — the same stuff that stores data and applications on your iPhone. These drives have been around for years, but they’ve been slow to make headway in the real world, in part because they’re more expensive than traditional hard drives. A 300GB flash drive sells for around $500, whereas a comparable hard drive is closer to $100. A 3 terabyte hard drive — which is about ten times larger — sells for around $350.

But in just the last 12 months, SSDs have turned the corner. They’re appearing in high-profile laptops such as Google’s Chromebooks and Apple’s brand-new MacBook Pros, and in the data center, many companies are realizing that they make economic sense even with their higher price tags.

In 2011, according to Jim Handy, an analyst with research outfit Objective Analysis, businesses purchased an estimated 79 million SSDs that connect to servers using the serial-ATA interface — i.e., the interface that traditional hard drives use. That’s a $2.2 billion market, says Handy, and he expects this to grow to 13 million devices and $3.6 billion in 2012.

“I think this is getting pretty common,” says Artur Bergman, the founder of Fastly, a San Francisco outfit that uses SSDs exclusively in providing a service that helps other businesses speed their delivery of pages over the net. “Though some people still have a hard time grasping it, these drives save a tremendous amount of money. They look more expensive, but when you need higher performance, you need way less of them.”

The Speech

About a year ago, Bergman gave a four-minute speech at a Silicon Valley conference attended almost exclusively by engineers who sit on the cutting edge of web infrastructure. He started by asking if anyone in the audience used SSDs in the data center, and less than 20 percent raised their hands. And when he asked who used only SSDs in their data centers, one person raised his hand — the head of engineering at Wikia, who had inherited his SSD-happy data center from Bergman, the outfit’s previous head of engineering.

Anyone who hadn’t raised a hand, Bergman said, was “wasting their life.” Yes, wasting their life. “I keep repeating that to every single individual I talk to, and what I get back is: ‘[SSDs are] too expensive,’” he said. “Actually, they’re cheaper.” Cost shouldn’t be measured by the price tag on an individual SSD, he said, but by how much you spend on drives across the data center in order to juggle the required information with each passing second.

One SSD, he said, can handle about 40,000 reads or writes a second, whereas the average hardware gives you about 180. And it runs at about one watt as opposed to 15 watts, which means you spend far less on power. “Do the math on how much you can save,” he said. In short, you need fewer servers to do the same amount of work. At Wikia, Bergman first installed SSDs on the company’s caching servers, used for providing quick access to data that repeatedly accessed by web surfers. Then, he moved them into the company’s database servers, where data stored more permanently. This provided so much additional speed, Bergman says, the caching servers were no longer needed.

When he gave the speech, Bergman had been preaching this same message for about two and half years — and few listened. But twelve months on, he says, it seems that the web is finally heeding his advice. Companies are constantly emailing him, just to let him know they’ve embraced SSDs.

Yes, many companies are still holding back, in part because they’re waiting for prices to come down even further, in part for other reasons. SSDs are not only more expensive than traditional hard drives, they can accept only so much data before they can’t accept any more. In other words, they have a limited lifespan.

But so do hard drives, which are prone to sudden and unexpected death. Bergman doesn’t see a SSD’s limited life as a big issue. “It’s a pretty good failure mode compared to a hard drive, which just takes longer and longer to write data before dying,” he says. At Wikia, he says, he replaced the company’s first SSDs after two years, and didn’t have any write problems before that.

“I don’t trust a hard drive after three years,” he says. “They don’t fail because they run out of write cycles, but they still fail.”

more @ http://www.wired.com/wiredenterprise/2012/06/flash-data-centers/