Comment by Maakuth

I believe the recommendation is to run btrfs on top of mdraid, which works fine. Meta is said to use btrfs, but apparently they don't care about the raid implementation, so there's nobody paying for that development.

OpenZFS works fine, but it can be tricky to install due to the license thing, not all distributions support it in their installer.

Bcachefs is said to be the up and coming contender for both, but it was merged to the mainline kernel in January, so probably at the moment it is tricky to install as well. I would think many of this year's distribution releases will make it available.