This resource (counter|metrics) are usually expressed in the following terms:
As utilization is a mean, it may have a high deviation that produce a saturation. Therefore a low utilization doesn't imply a low saturation.
They are part of SLI: Service Level Indicators
The data are generally collected as a gauge
Resource | Utilization | Saturation | Errors | Availability | |
---|---|---|---|---|---|
Disk IO | % time that device was busy | wait queue length | # device errors | % time writable | |
Memory | % of total memory capacity in use | swap usage | N/A (not usually observable) | N/A | |
Microservice | average % time each request-servicing thread was busy | # enqueued requests | # internal errors such as caught exceptions % time service is reachable | ||
Database | average % time each connection was busy | # enqueued queries | # internal errors, e.g. replication errors % time database is reachable |