usage: mkfs.btrfs [options] dev [ dev ... ] options: -A --alloc-start the offset to start the FS -b --byte-count total number of bytes in the FS -d --data data profile, raid0, raid1, raid10 or single -l --leafsize size of btree leaves -L --label set a label -m --metadata metadata profile, values like data profile -n --nodesize size of btree nodes -s --sectorsize min block allocation Btrfs v0.18-13-gb8420fa