Just out of curiosity....What are the (potential) show stoppers for implementing subvolume RAID levels in BTRFS? This is more and more interesting now that new RAID levels has been merged (RAID1c3/4) and RAID5/6 is slowly inching towards usable status.
I imagine that RAIDc4 for example could potentially give a grotesque speed increase for parallel read operations once BTRFS learns to distribute reads to the device with the least waitqueue / fastest devices.
