Run mongodb more securely and w/ small file sizes on startup (osx)

Create the mongod.conf and insert the config content.

sudo vim /usr/local/var/mongodb/mongod.conf

Create the org.mongo.mongod.plist file and insert the plist content.

sudo vim /Library/LaunchDaemons/org.mongo.mongod.plist

Assign the right permissions to it and load it.

sudo chown root:wheel /Library/LaunchDaemons/org.mongo.mongod.plist
sudo launchctl load /Library/LaunchDaemons/org.mongo.mongod.plist

Done.