Backend & systems·Scaling and load management
you work out from load tests how much traffic one instance handles, and how many you need for Black Friday.
Capacity planning
Also calledheadroom, load testing
Determining the resources required to meet demand at a target latency, with headroom for failure and spikes. It requires a measured per-instance capacity, not an assumed one. Plan for the loss of a zone or a region as well as the peak, or your headroom disappears exactly when you need it.