sudo blkid 
/dev/sda1: UUID="5e464b9a-c24c-401a-b896-6deaed2e83cf" TYPE="ext4" 
/dev/sdb1: LABEL="BTRFS_RAID" UUID="16beefd2-32a4-487c-addd-e919912609cc" UUID_SUB="37ddcd50-61f1-4674-b4ac-d0f8d8d0a579" TYPE="btrfs" 
/dev/sdc1: LABEL="BTRFS_RAID" UUID="16beefd2-32a4-487c-addd-e919912609cc" UUID_SUB="e1d5fd2c-b9cb-4523-9f47-76beebe25712" TYPE="btrfs" 
/dev/sdd1: LABEL="Hitatchi_1TB" UUID="3d5d7c68-11f7-4206-993b-21432f85b802" TYPE="ext4

sudo btrfs filesystem show 
Label: 'BTRFS_RAID'  uuid: 16beefd2-32a4-487c-addd-e919912609cc
	Total devices 2 FS bytes used 307.07GiB
	devid    1 size 1.82TiB used 1.12TiB path /dev/sdb1
	devid    2 size 1.82TiB used 1.12TiB path /dev/sdc1

fstab:

UUID=16beefd2-32a4-487c-addd-e919912609cc /media/raid 	  btrfs	  defaults,subvol=@ 0	    1