Finally, I’ve been waiting forever for this. btrfs is a mess and zfs in oracle jail forever. Finally we cna have good COW on linux without stupid hoops.
How is btrfs a mess?
RAID 5/6 is somewhat broken, and some people might consider the lack of built in encryption or support for a cache disk as problems. For some reason it seems popular to blame it for data loss.
That being said, it is my favorite file system and I never had problems with data loss, but I use ECC RAM on my desktop as is strongly recommended if you use btrfs or zfs (another potential downside).
The recommendation for ECC memory is simply because you can’t be totally sure stuff won’t go corrupt with only the safety measures of a checksummed CoW filesystem; if the data can silently go corrupt in memory the data could still go bad before getting written out to disk or while sitting in the read cache. I wouldn’t really say that’s a downside of those filesystems, rather it’s simply a requirement if you really care about preventing data corruption. Even without ECC memory they’re still far less susceptible to data loss than conventional filesystems.