NodeJS and mongod run on same instance and the host runs the run_test.sh command which utilizes httperf to generate a load of 500 requests per second. Running "db.serverStatus().connections" gives back "2" (one for the shell running the command and one for the node js application) while the test is running.

While testing same code under 2.1.18, the connection opens the five connections under the same load which allows it to handle ~500 requests per second rather than the ~100 request per second on 2.2.22.