Shutting down mongod while mongodump is running Can we shutdown mongod instance while the mongodump is running? Does mongodump operate by itself or it is a client for a mongod server?
No we cannot . other wise it will give error of server not reachable. As it  connects to DB via mongod service like normal connections. follow below link https://docs.mongodb.org/v3.0/tutorial/backup-and-restore-tools/  clearly mentioned that Mongos or mongod service should be running on machine.