The USE Method can be summarized as:
For every resource, check utilization, saturation, and errors. It's intended to be used early in a performance investigation, to identify systemic bottlenecks.
Terminology definitions:
resource: all physical server functional components (CPUs, disks, busses, ...) [1] utilization: the average time that the resource was busy servicing work [2] saturation: the degree to which the resource has extra work which it can't service, often queued errors: the count of error events
The metrics are usually expressed in the following terms:
utilization: as a percent over a time interval. eg, "one disk is running at 90% utilization". saturation: as a queue length. eg, "the CPUs have an average run queue length of four". errors: scalar counts. eg, "this network interface has had fifty late collisions".
View metrics that prometheus knows about: http://localhost:9090/api/v1/label/__name__/values