MongoDB: exception in initAndListen: 20 Attempted to create a lock file on a read-only directory: /data/db, terminating

Question

I created /data/db in root directory and ran ./mongod:

[initandlisten] exception in initAndListen: 20 Attempted to create a lock fi         


        

Answer 1

On a Mac, I had to do the following:

sudo chown -R $USER /data/db
sudo chown -R $USER /tmp/

because there was also a file inside /tmp which Mongo also needed access