Yes, this is similar to my fairly recent experience with btrfs. While it's competitive on paper and there are several meta-arguments in its favor (being in main

Yes, this is similar to my fairly recent experience with btrfs. While it's competitive on paper and there are several meta-arguments in its favor (being in mainline, for example), the cold hard facts just don't stack up. btrfs fares far worse and requires much more tuning than a generic ZFS installation. A great example is that if you ever try to run a database or a large virtual machine on a btrfs mount, you'll quickly become acquainted with chattr +C for "nocow". Any write-intensive applications grinds the filesystem to a halt until you disable the copy-on-write functionality for that file specifically, making it so snapshots, etc., are ineffective and the FS stops tracking the changes that would make them possible. Whereas on ZFS, like any application that uses fixed block sizes, virtualization and databases _may_ require some alignment tuning to avoid a read-modify-write cycle, and ZFS works without fuss from that moment on. I know that Facebook is investing heavily in btrfs right now, but to be frank, I don't see the point. btrfs doesn't have its youth as an excuse anymore and the core issues that exist seem like they're pretty fundamental. It's a gargantuan waste of effort when people could just take the tack that Ubuntu has taken and decide all that FUD around the CDDL, kicked up by fears that the commercial Unices were plotting to take their revenge on Linux, that maybe all that isn't super relevant anymore, and they can just start shipping ZoL.