@TindrasGrove @becomethewaifu The better question is: Why did they not have any offline backups? Talk about negligence...

That being said, online backups tend to be more reliable (outside of incidents like this) because dynamic processes with constant scrubbing & repair of the data are an option.

If a tape in storage gets partially corrupted or sticks, that's it, it's partly or entirely worthless. And while redundant tapes are a good idea, if the degradation is partly due to storage conditions, they might all be faulty in intersecting/overlapping manner.

(The better option would be airgapped "offline" backups, so that the dynamic repair processes can be used but networked attacks aren't an option.)