(BeagleBoneBlack)ubuntu@localhost:~$ df -a | grep writable
/dev/mmcblk0p4               59257132 168904  56061888   1% /writable
/dev/mmcblk0p4               59257132 168904  56061888   1% /etc/writable
/dev/mmcblk0p3                 999320 484132    446376  53% /writable/cache/system
lxcfs                               0      0         0    - /writable/system-data/var/lib/apps/lxd/0.21-1/lxcfs