Hmmm, it's been a long long time since I actually had a failed drive (and also I don't use zfs), but from what I remember of my last failing drive 20 years ago, the drive was able to detect that sectors had been corrupted, and then failed the read rather than just returning silently corrupted data. If my memory is correct, replacing random bytes on disk wouldn't actually reflect the typical way data corruption manifests itself.

I always thought that the reason zfs did its extensive CRC checks was primarily to detect data corruption while it was in RAM or over the network, with a side effect that in the rare cares that data on disk got corrupted without the drive detecting it because the CRC was still valid, it'd also be spotted.

But anyway, it might be worth testing by replacing some of the disk images with actually truncated ones so that there are holes when reading, so that it returns an actual read error rather than junk data.

> The DVA was correct, the sector math was correct, the dd command was correct. The right place, the wrong mental model.

God the intensity is tiresome. Whether or not it's AI slop, it's also bad writing. Things can be fun or interesting or worthwhile without being a harrowing battle of discovery!