@cbleslie @queenofhatred zfs has several features which are very helpful for data integrity and other protections
- data checksumming with cryptographic hashes to detect bitrot
- filesystem-integrated RAID, which means it's aware of what it's replicating
- the two combination of those two with regular scrubs (reading out the entire fs) allows restoring corrupted redundant copies (so for example if you get a bit flip on one drive, it can safely be fixed because you know the other drives have correct data)
- built-in data encryption (also a thing on ext4) which is superior to dm-raid (https://sockpuppet.org/blog/2014/04/30/you-dont-want-xts/)

additionally, the CoW architecture allows some really nice things:
- "reflinks", which are similar in concept to hard links (multiple directory entries can point to the same data blocks), but can safely be written over
- atomic snapshots, which can save the state of the filesystem at any point in time, and can be browsed later to recover deleted files, or even replicated to another drive as a backup solution (this is what saved me, my SSD failed but I've been replicating hourly snapshots to a raid1 of HDDs for backups, now I can restore things to the exact way they were before)

a lot of this applies to btrfs (though it is considered inferior in its implementation) and bcachefs (less mature) as well