This is the result, what do you make of it?
the /temp folder is probably my externally connected drive being:
/tmp/run/mountd/sda2
3.20 TB / 3.58 TB
6% (201.45 GB)
Can the /mnt folder be the problem?
root@turris:~# cd /
root@turris:/# du -hd 1
0 ./sys
0 ./overlay
2.4M ./boot
1.5M ./bin
0 ./srv
320.0K ./www
4.0K ./rom
4.1M ./sbin
200.2G ./tmp
4.0K ./dev
118.3M ./usr
0 ./proc
10.7M ./lib
6.4G ./mnt
12.0K ./root
4.6M ./etc
8.0K ./run
206.7G .
root@turris:/#