permission denied on mongod.lock, despite it being owned by mongodb
It works after I did:

sudo chmod +r /run/media/minze/ssd
sudo chmod +x /run/media/minze/ssd


I don't understand why.

mongodb.lock is located in /run/media/minze/ssd/mongodb/mongodb.lock

ls -lha gives me (permissions of '.' are important here):

drwxr-xr-x 8 minze   minze   4.0K Dec  3 17:40 .
drwxr-xr-x 3 root    root      60 Dec  3 10:49 ..
drwx------ 2 root    root     16K Oct 15 20:24 lost+found
drwx------ 4 mongodb mongodb 4.0K Dec  3 17:54 mongodb


now