I don't know how much the size of the metadata chunk matters with this, but I see 256M, 512M, and 1G metadata chunks on my file systems. Try this for length only, which is in bytes: $ sudo btrfs insp dump-t -t chunk /dev/nvme0n1p7 | grep METADATA This will show the entire item, A5 might be needed to show both devuuids, since you're using raid1, and might want to know on which device the chunk is located; the devuuid is found in the superblock. $ sudo btrfs insp dump-t -t chunk /dev/nvme0n1p7 | grep -A4 -B1 METADATA Chris Murphy
