What happens when you write a petabyte of data to an SSD

Last Updated on July 3, 2018 by Dave Farquhar

If you’re concerned about SSD reliability, Tech Report has good news for you: They attempted to write a petabyte of data to six SSDs, and three of them survived. Considering the drives were rated for a 200 TB life expectancy, that’s impressive. In fact, even the worst drives outlived their 200 TB life expectancy. And all started behaving oddly long before their demise, giving you ample warning to do something in advance–something you can’t say about evil nasty platters of spinning rust–perhaps better known as traditional hard drives.

The first drive to fail, if you’re wondering, was the Samsung 840, which uses cheaper TLC memory. But even the Samsung 840 outlived its projected life expectancy. Since other companies are undercutting the 840’s price even with MLC memory these days, I’m not sure what Samsung’s plans for the 840 are. For the time being, I doubt you’ll be buying one. One of the drives that’s still going after a petabyte of writes is a costlier Samsung MLC drive.

Odds are many of us will struggle to ever write 200 TB to a drive–literally the equivalent of filling it to capacity 1,024 times. Hard drives fail when their physical components wear out; SSDs fail when their memory chips run out of write-erase cycles. So SSDs fail with a lot more warning, and tend to fail predictably. The 15-year-old Quantum Fireball in my basement, which I think of immortal for its longevity, could die the next time I power it up, or it could last another 10 years. I don’t know. But an SSD can pretty reliably tell me the minimum number of write cycles it has left. And when either a hard drive or an SSD starts to fail, they tend to throw error messages. A modern operating system will usually relay those errors to you. And if it doesn’t throw an error, you’ll get bad sectors, which lead to write errors, which ought to make you suspicious. I have always replaced drives when I started getting bad sectors, and the strategy has never failed me.

Realistically, we’re still at the point with SSDs that they’ll outlive their usefulness before they’ll run out of write cycles, realistically. By that I mean you’ll probably replace it because you can’t store enough on it anymore to be useful. To increase the possibility of that, be sure to check your SSD alignment, and align it if needed. This improves both longevity and performance.

In other SSD news today, it seems PNY and Kingston have been overbuilding their drives just long enough to pile up a nice collection of good reviews, then switching to cheaper, lower-performing components. That’s disappointing behavior from both companies, especially Kingston, who has been the gold standard for memory since the late 1980s. I recommend buying from companies that own foundries–Intel, Micron/Crucial, Samsung, Sandisk, and Toshiba–because they get first dibs on the best chips and thus have an advantage when it comes to longevity, but apparently having higher profit margins helps too.

I’m a performance and reliability fiend, as anyone who’s known me for a few years will attest, so I recommend SSDs.

SSDs can die suddenly due to power loss, but there’s a fix for that. It’s a lot better than the bad old days when we put up with Zip drives.

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