# btrfs fi show
Label: 'data'  uuid: f4479ed6-67a8-4a76-b87e-f8a0c8111d91
        Total devices 2 FS bytes used 557.59GiB
        devid    1 size 2.72TiB used 892.06GiB path /dev/sdb3
        devid    2 size 2.72TiB used 892.06GiB path /dev/sda3

Label: 'boot'  uuid: d071e925-f1ef-411b-af8e-458504c05d28
        Total devices 2 FS bytes used 338.11MiB
        devid    1 size 1.00GiB used 879.00MiB path /dev/sda2
        devid    2 size 1.00GiB used 879.00MiB path /dev/sdb2


# btrfs fi show
Label: 'data'  uuid: f4479ed6-67a8-4a76-b87e-f8a0c8111d91
        Total devices 2 FS bytes used 557.59GiB
        devid    1 size 2.72TiB used 892.06GiB path /dev/sdb3
        devid    2 size 2.72TiB used 892.06GiB path /dev/sda3

Label: 'boot'  uuid: d071e925-f1ef-411b-af8e-458504c05d28
        Total devices 2 FS bytes used 338.17MiB
        devid    1 size 1.00GiB used 656.00MiB path /dev/sda2
        devid    2 size 1.00GiB used 837.62MiB path /dev/sdb2


# btrfs fi usage /boot
Overall:
    Device size:                   2.00GiB
    Device allocated:              1.72GiB
    Device unallocated:          290.00MiB
    Device missing:                  0.00B
    Used:                        676.22MiB
    Free (estimated):            409.06MiB      (min: 409.06MiB)
    Data ratio:                       2.00
    Metadata ratio:                   2.00
    Global reserve:               16.00MiB      (used: 0.00B)

Data,RAID1: Size:601.38MiB, Used:337.31MiB
   /dev/sda2     601.38MiB
   /dev/sdb2     601.38MiB

Metadata,RAID1: Size:245.62MiB, Used:800.00KiB
   /dev/sda2     245.62MiB
   /dev/sdb2     245.62MiB

System,RAID1: Size:32.00MiB, Used:16.00KiB
   /dev/sda2      32.00MiB
   /dev/sdb2      32.00MiB

Unallocated:
   /dev/sda2     145.00MiB
   /dev/sdb2     145.00MiB





# btrfs fi usage /
Overall:
    Device size:                   5.44TiB
    Device allocated:              1.74TiB
    Device unallocated:            3.70TiB
    Device missing:                  0.00B
    Used:                          1.09TiB
    Free (estimated):              2.18TiB      (min: 2.18TiB)
    Data ratio:                       2.00
    Metadata ratio:                   2.00
    Global reserve:              512.00MiB      (used: 0.00B)

Data,RAID1: Size:881.00GiB, Used:547.77GiB
   /dev/sda3     881.00GiB
   /dev/sdb3     881.00GiB

Metadata,RAID1: Size:11.00GiB, Used:9.81GiB
   /dev/sda3      11.00GiB
   /dev/sdb3      11.00GiB

System,RAID1: Size:64.00MiB, Used:160.00KiB
   /dev/sda3      64.00MiB
   /dev/sdb3      64.00MiB

Unallocated:
   /dev/sda3       1.85TiB
   /dev/sdb3       1.85TiB