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Comment by bayindirh | Hacker News Reader

The disk failure rates are very low when compared to decade ago. I used to change more than a dozen disks every week a decade ago. Now it's an eyebrow raising event which I seldom see.

I think following Backblaze's hard disk stats is enough at this point.

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Backblaze reports an annual failure rate of 1.36% [0]. Since their cluster uses 2,400 drives, they would likely see ~32 failures a year (extra ~$4,000 annual capex, almost negligible).

[0] https://www.backblaze.com/cloud-storage/resources/hard-drive...

Their rate will probably be higher since they are utilizing used drives. From the spec:

2,400 drives. Mostly 12TB used enterprise drives (3/4 SATA, 1/4 SAS). The JBOD DS4246s work for either.

Not necessarily, since disk failures are typically U-shaped.

Buying used drives eliminates the high rate of early failure (but does get you a bit closer to the 2nd part of the U-curve).

Typically most drives would become more obsolete before hitting the high failure rate of the right side of the U-curve from longevity (7+ years)

I bet you still have a higher early failure rate because of the stress from transportation, even if there's no funny business. And I expect some funny business because used enterprise drives often come with wiped SMART data, some drives may have been retired by sophisticated clients who decided they were near failure.

Physically moving the drive tends to reset the U-shape. Some will be damaged.

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