[amluto]

This particular bug won’t be easily caught just by testing backups, as the bytes in the filesystem never actually change. So you can diff the bytes on disk between the live system and the backup, and they’ll match.

I like to keep a separate database of what files I expect to have along with their hashes. The off-the-shelf tooling for this is weak, to say the least. Even S3’s integrity checking support is desultory at best, and a bunch of S3 clones don’t implement it at all (cough minio cough).