This guide will help you migrate from the built-in Meteor mongo server to an external mongo server.
Before starting make sure meteor is running.
Then run: mongodump -h 127.0.0.1 --port 3001 -d meteor
It'll dump the database in a folder called dump.
Then install mongodb on your system. Please see the in one of our guides for your current OS
Once Mongo is installed restore the data using: mongorestore -d meteor dump/meteor
If you want to use a different database, you'd take this as your opportunity to change the database name. Replacing -d meteor with your desired database name.
Then follow the remainder of the guide on for your current OS.