[KozmoNau7]

Not that I know the exact hardware and circumstances, but in my experience that sounds like a hardware issue, either a buggy controller or a failing disk.

Zfs -with it's similar checksumming and integrity features- would likely have faced similar issues.

[yjftsjthsd-h]

It happened months apart and I never saw it report data errors. It could still be hardware, of course (I haven't tried to run ZFS on the same hardware), but even if it was a hardware fault this isn't an impressive failure mode. Like... what are the odds that a random hardware bug breaks BTRFS metadata in such a way that I can't even mount the filesystem, and never just breaks random files such that I get an isolated read error?