Comment by ghaff

I'm not super-plugged into Fedora these days. Red Hat has long been pretty comfortable with a more conventional file system (think it's still XFS out of SGI by default) plus volume management for RHEL. ZFS was a non-starter for licensing reasons and Oracle; btrfs just wasn't there. I suspect things could have played out differently had Oracle relicensed ZFS once upon a time but that ship has likely sailed in a variety of ways.