Btrfs For Linux 5.1 Brings Configurable Zstd Compression Level, A Number Of Fixes

[PreparationH67]

Btrfs just keeps going and will repair itself the moment you plug in a new disk. With RAID6 you need to rebuild the array, which takes the system offline for a while and also it increases the risk of a cascade failure.

I don't think you understand whats going on in both cases. That repair is still a rebuild of the array, it just happens to be a much faster rebuild operation. While keeping the array offline is the practice when replacing a single failure, it is not actually required. RAID 5/6 is still used in numerous professional storage setups and its not uncommon to see it paired with RAID 0 to augment the performance (RAID 50/60). It depends on the use cases for the data.

[gilboa]

More like the the corner case that noone really cares about. Users with real valuable data use RAID10, the majority of the rest doesn't bother with RAID at all. RAID5/6 is for hobbyists and perhaps the odd small business that doesn't have everything hosted in the cloud. At any rate, such users don't seem prepared to actually do anything to fix it, or to pay for someone to fix it.

Funny, I've got couple of PB of storage that uses complex setups above RAID6 (E.g. RAID60 in mirror setup, RAID60 w/ glusterfs cluster, etc).
And no, if you need to locally host constantly changing data in 100's of TB, hosting in a cloud, is a huge no, no, unless you own an ISP.
Care to share your experience in the matter?

- Gilboa