Following my post MySQL/ZFS Performance Update, a few people have suggested I should take a look at BTRFS (butter-FS, b-tree FS) with MySQL. BTRFS is a filesystem with an architecture and a set of features that are similar to ZFS and with a GPL license. It is a copy-on-write (CoW) filesystem supporting snapshots, RAID, and [&]

https://www.percona.com/blog/taking-a-look-at-btrfs-for-mysql/