This is a long shot but I thought I'd post this here just in case we had any closet btrfs experts in the tree. LUKS btrfs volume spanning SSD and HDD My assumption is that the btrfs volume will grow as needed filling the SSD first (less 20% unallocated overprovision space) and then begin to fill the HDD. Concern: I've activated some of the btrfs SSD specific features in fstab (discard,ssd,ssd_spread,etc). What will happen when fstab attempts to apply these SSD specific mount options to the HDD? Anything? Nothing? Everything? Doom? This is a simple btrfs volume with no raid or bcache. I like the idea of using the LVM-esque feature of btrfs but maybe I'd be better off with standard partitions so that I can properly define mount options to the media (SSD or HDD) being mounted. Thoughts? This is a long shot but I thought I'd post this here just in case we had any closet btrfs experts in the tree.