#sre # RED & USE There are two main lines of thoughts on the correct metrics to collect and display in a dashboard for a given service: - The [USE method](http://www.brendangregg.com/usemethod.html) (as in Utilization, Saturation, Errors) is conceptually a white box method that focuses on internal service metrics. - The [RED method](https://thenewstack.io/monitoring-microservices-red-method/) (as in Request rate, Errors and Duration) is conceptually more of a black box approach that focuses on the externally observable metrics. At Google, SREs use the [four golden signals](https://landing.google.com/sre/sre-book/chapters/monitoring-distributed-systems/#xref_monitoring_golden-signals), which roughly corresponds to the RED method plus the saturation metric. ![[Image-29-10-2024.png]] # USE **Utilization**: the percentage of time a resource has been utilized **Saturation**: the degree to which the resource has extra work that it can't service; often queued **Errors**: the number of errors reported by each resource These measures should be collected for the significant resources of a system, typically memory, CPU, disk, and network. # RED The RED method consists of observing the following metrics: **Rate of requests:** generally in the form of requests per second. **Errors:** Number of requests that returned an error condition. **Duration:** The time it took to process the requests.