these are the three main lists of golden signals today: From the Google SRE book: Latency, Traffic, Errors, Saturation USE Method (from Brendan Gregg): Utilization, Saturation, Errors RED Method (from Tom Wilkie): Rate, Errors, and Duration
You can see the overlap. USE is about resources with an internal view, while RED is about requests and real work, with an external view.
focus on signals: Request Rate — request rate, in requests/sec. Error Rate — error rate, in errors/sec. Latency — response time, including queue/wait time, in milliseconds. Saturation — how overloaded something is, directly measured by things like queue depth (or sometimes concurrency). Becomes non-zero when the system gets saturated. Utilization — how busy the resource or system is. Usually expressed 0–100% and most useful for predictions (saturation is usually more useful for alerts).
