Finally, someone with enough volume to test significant numbers of drives comes clean. There are drives to buy and drives to avoid.
Backblaze - the cloud backup company - continues to share their drive experience with us onesy-twosy buyers. It's informative.
Methodology
Backblaze, which open sourced their Storage Pod a few years ago, is now giving drive failure rates. They currently have over 27,000 consumer grade drives spinning in Backblaze storage pods.
Almost 13,000 each are Seagate and Hitachi drives, almost 3000 Western Digital drives and a too small for statistical reporting smattering of Toshiba and Samsung drives.
One cool thing: Backblaze buys drives the way you and I do: they get the cheapest drives that will work. Their workload is almost hundred percent write. Because they spread the incoming writes over several drives their workload isn't very performance intensive either.
Also, like you and me, they are willing to spend a little more for a more reliable drive but not a lot more. And unlike you and me they track every single drive that they install.
They measure the annual failure rate (AFR) rather than MTBF because that's an easier number to understand. They count as a failure anytime they have to replace a drive. Of course, vendors report that about half of all returned drives have no trouble found – but I like Backblaze's definition better.
Read more at: Who makes the best disk drives? | ZDNet