This info on SSD failure appeared in a MacInTouch post:
The papers largely focus on enterprise and cloud-scale systems and tell a consistent story. The main cause of data loss is NAND flash die failures.
Most flash chips consist of two dies packaged together, and when failures occur, it's typically a single die that fails. While individual NAND flash cells have a limited number of writes, mitigation strategies in modern SSD controllers ensures those limits are rarely reached.
In a 256GB SSD today, there could be as few as 16 dies on 8 chips. Lose a single die and there goes ≈16GB of data. Better than a disk drive head crash that destroys the entire drive, but sub-optimal.
Apple engineers are aware of the SPOF problem, as evidenced by their decision to create not one but two recovery volumes on the SSD. Maybe they were even smart enough to ensure that those volumes are spread across different dies in separate chips.
On a Mac since 1984.
Currently: 24" M1 iMac, M2 Pro Mac mini with 27" BenQ monitor, M2 Macbook Air, MacOS 14.x; iPhones, iPods (yes, still) and iPads.
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