# btrfs fi show /var
Label: none  uuid: 8de0ca54-5828-4c4a-9677-f17e02d852ae
        Total devices 4 FS bytes used 11.71GiB
        devid    1 size 465.66GiB used 46.04GiB path /dev/sda3
        devid    2 size 4.00GiB used 1.00GiB path /dev/loop0
        devid    3 size 4.00GiB used 3.00GiB path /dev/loop1
        devid    4 size 4.00GiB used 3.00GiB path /dev/loop2
# btrfs fi df /var
Data, single: total=41.01GiB, used=11.58GiB
System, DUP: total=8.00MiB, used=16.00KiB
System, single: total=4.00MiB, used=0.00B
Metadata, RAID1: total=5.00GiB, used=127.47MiB
Metadata, DUP: total=1.00GiB, used=2.03MiB
Metadata, single: total=8.00MiB, used=0.00B
GlobalReserve, single: total=79.19MiB, used=0.00B