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Comment by aperrien | Hacker News Reader

As a side question, how can you tell how many writes a regular drive has sustained? Say, like the one in my desktop or laptop?

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SSDs tend to report this as SMART ID 241, total LBAs written.

I haven't seen this on any rotational drives. I actually find that puzzling, as it's a very interesting stat to track.

It's an interesting stat to track, but not one that physically was an endurance metric for spinning drives, which is probably why it didn't appear until SSD vendors tracked it because, as much more obvious here, it's a very serious thing to keep track of sometimes.

I thought the main endurance metric for spinning disks is total bytes read or written? AKA time where the head is right up close to the platter. That doesn't seem too far off to track both total read and write IOs and/or bytes.

I believe (but can't cite any sources for that) that unless the head is parked (which either only happens when the disk goes to sleep, or at least after somewhat extended times of inactivity) HDD heads are always right above the platter, i.e. regardless of whether something is being read, written, the head moved, or there being a (short) activity pause. Assuming that the number of repolarisations of the magnetic substrate is not limiting, while total parking/sleep times should have a +-strong correlation with life times (although it might be negative, too, when the periods are too short, due to parking cost?), total bytes read/written should only have a weak correlation (by being correlated with the former). I am not a storage device specialist.

sudo smartctl -a /dev/sda | grep Total_LBAs_Written

Please do not depend on ID 241 - it may vary with manufacturer [1]

[1] http://www.samsung.com/global/business/semiconductor/minisit...

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