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Consumer-Grade SSDs Survive Two Petabytes of Writes
crookedvulture writes The SSD Endurance Experiment previously covered on Slashdot has reached another big milestone: two freaking petabytes of writes. That's an astounding total for consumer-grade drives rated to survive no more than a few hundred terabytes. Only two of the initial six subjects made it to 2PB. The Kingston HyperX 3K, Intel 335 Series, and Samsung 840 Series expired on the road to 1PB, while the Corsair Neutron GTX faltered at 1.2PB. The Samsung 840 Pro continues despite logging thousands of reallocated sectors. It has remained completely error-free throughout the experiment, unlike a second HyperX, which has suffered a couple of uncorrectable errors. The second HyperX is mostly intact otherwise, though its built-in compression tech has reduced the 2PB of host writes to just 1.4PB of flash writes. Even accounting for compression, the flash in the second HyperX has proven to be far more robust than in the first. That difference highlights the impact normal manufacturing variances can have on flash wear. It also illustrates why the experiment's sample size is too small to draw definitive conclusions about the durability of specific models. However, the fact that all the drives far exceeded their endurance specifications bodes well for the endurance of consumer-grade SSDs in general.
Just out of curiosity, how well do traditional HDD fare in comparison?
Great, so now we just need to fix the sudden random failures where the drive completely fails but it is 6 months old and showed no signs of degradation. A coworker of mine just had that happen with a Crucial SSD.
Unfortunately these tests don't say much about the drives you can buy NOW, and write endurance in consumer drives is probably getting worse as geometry shrinks and relentless price pressure causes corners to be cut. It's good that the Samsung 840 Pro is holding up so well (its predecessor the 830 was also ridiculously durable) but it's now replaced by the 850 Pro which uses radical new technology (stacked chips). The Intel 320 was also very durable so the failure of the 335 doesn't bode very well for the idea that newer models should hold up better than older ones.
Write wear isn't everything anyway. Another thing to test is whether the drive can brick if the power fails while the drive is writing. Better drives have capacitors to deal with this event. Consumer drives lack them and can lose data or fail unrecoverably.
However my company found that in testing, the more number of writes to a flash device, the shorter time before the data is leaked out. So after 10,000 writes to the same location, I can read the data a month later with no errors, but at 50,000 writes I start getting errors after about 2 hours. It seems like flash storage is like a bucket of water, each erase pokes a tiny hole in the bucket. After awhile those tiny holes add up and the bucket leaks pretty fast. So long term storage is not as safe as a conventional hard drive.
From my experiences, most of SSD failures come from dead controllers and not wear. Or bad firmware, I'm looking at you Crucial and your 5000 hour bug. Also your weird incompatibles on your MX100 series.