For the command that starts the
mongod --port “PORT” --dbpath “YOUR_DB_DATA_PATH” --replSet “REPLICA_SET_INSTANCE_NAME”
dbpath is where all of the DBs are stored right, so if I am setting up the primary node for example it would write and read the data to the specified DBs from the
dbpath and then would forward the data to the Secondary nodes for replication. In the Secondary nodes, the replicated data forwarded from the Primary node will be stored in the
dbpath as well a reading of the dataset will be made from it by the client application.