Ask HN: How do you debug performance issues in Node.js applications at scale?

[ratpik]

Traffic = About 0.5 million requests/minute (HTTPS + WSS) and about 80K concurrent websocket connections with intermittent spikes in traffic.

Runs on managed infrastructure on AWS. Almost all the requests are Network (HTTPS) I/O intensive and about a third are Database (MySQL) I/O intensive.