Identifying "disk usage" inside a Linux Filespace mount-point through du -b <path> which will calculate the size of the Filespace in bytes.
Other handy options for `du` are: `-s` (summary), `-h` (human readable), `--max-depth` (specifies folder depth for the final report).
Example: du -bhs <path>
Please note, that this calculates the size of the Filespace (mount-point) and does not include the disk space, used by the Lucid in cache or metadata (the internal `.lucid`) folder.