The level of simplicity of ZFS has no equivalent in Linux; the whole lvm stack is a fuckup from a usability perspective. Half a dozen distinct commands working on different layers that - more often than not - are conceptual. ZFS has been around for almost 20 years now. It was production ready more than 10 years ago, when it was open-sourced. Having your systems 1 or 2 versions behind the mainline is good practice in every mission-critical piece of software.