Why should it matter? It's an extremely niche technology that's only interesting to some home users. I see no reasons why other users should care about a RAID level they're not interested in.

(I don't use btrfs or any other COW filesystem because of significantly worse performance with some kinds of workloads, but it has nothing to do with maturity of any of them.)

> Why should it matter? It's an extremely niche technology that's only interesting to some home users.

I use RAID-Z2 in lots of places for bulk storages purposes (HPC).

There's a reason why Ceph added erasure coding:

* https://ceph.io/en/news/blog/2017/new-luminous-erasure-codin...

* https://docs.ceph.com/en/latest/rados/operations/erasure-cod...

When you're talking about PB of data, storage efficiencies add up.

Wtf? This is a bizzare take. Facebook poured in millions of dollars of R&D into btrfs.

but they likely put money into features which they are interested in, and not raid56

Yes but you will lose data if you are writing to your array when the power goes out. RAIDZ (ZFS) does not have this problem. See BTRFS RAID5 write hole.