Exam Professional Cloud DevOps Engineer topic 1 question 143 discussion

Answer B seems to be correct for latency and windows-based. "service will be addressed in fewer than 300 ms at least 90% of the time per calendar month. "

it asks to be fewer than 300ms hence it excludes C and D which are availability metrics. Then it cares about the percentage of requests(90%) but never mentioned windows requirements hence A. Actually mentioning calendar in the question is a trick, it misled you to think about a time range, but both request-metrics and windows-metrics would require a setting of compliance periods, this could be either calendar or rolling-windows https://cloud.google.com/stackdriver/docs/solutions/slo-monitoring#compliance-period

https://cloud.google.com/stackdriver/docs/solutions/slo-monitoring#slo-type-request

The request-based method of evaluation will calculate the percentage of requests that meet the latency threshold of 300 ms over the entire calendar month.

To create a Cloud Monitoring Service Level Objective (SLO) for a service with the requirement of ensuring that requests are addressed in fewer than 300 ms at least 90% of the time per calendar month, the recommended approach is (option A). Select a latency metric for a request-based method of evaluation. Latency metrics, which measure the time it takes for requests to be processed, are appropriate for evaluating the specific performance requirements outlined in the scenario. By selecting a latency metric for a request-based method, such as P95 (percentile 95), you can precisely measure and evaluate the desired performance level—requests being addressed in fewer than 300 ms at least 90% of the time. This approach aligns with the specific performance criteria and allows for a granular assessment of the service's responsiveness.

Vote A

I think A is correct answer. Window-based metrics evaluate the percentage of time the condition is met. https://cloud.google.com/stackdriver/docs/solutions/slo-monitoring#slo-types