Top Node.js metrics to watch: https://www.oreilly.com/ideas/top-nodejs-metrics-to-watch
The node.js Profiling Guide that Hasn’t Existed - Profiling node.js Applications - Part 1: http://www.willvillanueva.com/the-node-js-profiling-guide-that-hasnt-existed-profiling-node-js-applications-part-1/
The node.js Profiling Guide that Hasn’t Existed - Finding a potential memory leak using memwatch - Part 2: http://www.willvillanueva.com/the-node-js-profiling-guide-that-hasnt-existed-finding-a-potential-memory-leak-using-memwatch-part-2/
The node.js Profiling Guide that Hasn’t Existed - Finding The Cause of a Memory Leak Using Heap Snapshots - Part 3: http://www.willvillanueva.com/the-node-js-profiling-guide-that-hasnt-existed-finding-the-cause-of-a-memory-leak-using-heap-snapshots-part-3/
Debugging Node.js in production: http://techblog.netflix.com/2015/12/debugging-nodejs-in-production.html