[throw0101d]

> The disk is going to report an uncorrected error for one of them.

Emperical evidence has shown otherwise: I have regularly gotten checksum error reports that ZFS has complained about during a scrub.

The ZFS developers have said in interviews that disks, when asked from LBA 123 have returned the contents of LBA 234 (due to disk firmware bugs): the on-disk checksum for 234 is correct, and so the bits were passed up the stack, but that's not the data that the kernel/ZFS asked for. It is only be verifying at the file system layer than the problem was caught (because at the disk layer things were "fine").

A famous paper that used Google's large quantity of drives as a 'sample population' mentions file system-level checks:

* https://www.cs.toronto.edu/~bianca/papers/fast08.pdf

See also the Google File System paper (§5.2 Data Integrity):

* https://research.google/pubs/the-google-file-system/

Trusting drives is not wise.