USE Method (from Brendan Gregg): Utilization, Saturation, and Errors
Efficiency of use. Average resource usage time for
service requests, or the portion of the resource's capacity that is currently occupied.
For example, the consumption of a disk that is 90% occupied will be 90%.
Saturation. The degree of resource congestion or the length of the request queue,
which are waiting for the resource to become available. For example, if running on
ten processes are waiting on the processor, the processor load will be
equal ten.
Mistakes. The number of times the operation on this resource has failed. For example-
For example, a disk with bad sectors can have as many errors as
25 failed reads.
RED Method (Requests-Errors-Duration): Rate, Errors, and Duration
number of requests received per second;
percentage of queries that returned an error;
Request duration (also known as latency).
