disk usage

Looking at disk usage on any of these must be done using a tool built for it if you want an accurate measurement. General purpose tools like du will be inaccurate as they do not count things like duplicate copies in snapshots.

 sudo btrfs fi usage -T /
[sudo] password for waylon:
    Device size:                 465.26GiB
    Device allocated:            251.06GiB
    Device unallocated:          214.20GiB
    Device missing:                  0.00B
    Device slack:                    0.00B
    Used:                        234.44GiB
    Free (estimated):            227.37GiB      (min: 120.27GiB)
    Free (statfs, df):           227.37GiB
    Data ratio:                       1.00
    Metadata ratio:                   2.00
    Global reserve:              478.88MiB      (used: 0.00B)
    Multiple profiles:                  no

                  Data      Metadata System
Id Path           single    DUP      DUP      Unallocated Total     Slack
-- -------------- --------- -------- -------- ----------- --------- -----
 1 /dev/nvme1n1p2 239.00GiB 12.00GiB 64.00MiB   214.20GiB 465.26GiB     -
-- -------------- --------- -------- -------- ----------- --------- -----
   Total          239.00GiB  6.00GiB 32.00MiB   214.20GiB 465.26GiB 0.00B
   Used           225.82GiB  4.31GiB 64.00KiB

-T for tabular format

mounting the drive

sudo mkdir /mnt/nvme1n1p2/
sudo mount -o subvol=/ /dev/nvme1n1p2 /mnt/nvme1n1p2

mounting a snapshot



sudo btdu /mnt/nvme1n1p2

 btdu v0.5.0 @ /mnt/nvme1n1p2
--- / -----------------------------------------------------------------------------------  ~5.974 GiB [          ] /<DUP>  ~239.1 GiB [##########] /<SINGLE>

--- Details: ----------------------------------------------------------------------------
- Full path: /mnt/nvme1n1p2/
- Average query duration: 0.0002558 seconds
- Represented size: ~245.0 GiB (607659 samples), ±0.0 B
- Logical offsets: ..., 2659587804610, 2608834997278, 2688762158568

--- Explanation:
Welcome to btdu. You are in the hierarchy root; results will be arranged according to
their block group and profile, and then by path.

Use the arrow keys to navigate, press ? for help.

 Samples: 607659  Resolution: ~422.8 KiB