Exams / DVA-C02 / Custom metrics and alarms / Question 2
DVA-C02 practice question: Custom metrics and alarms (2 of 2)
Troubleshooting and Optimization A free question from our original DVA-C02 practice exam. Try it, then open the answer to see why each option is right or wrong.
An application publishes a custom metric named QueueLagSeconds with PutMetricData. Operations want an alarm that evaluates this metric every 10 seconds so they are notified of spikes quickly. What must the developer do?
Choose one answer.
- AA. Publish the metric as a high-resolution metric and create an alarm with a period of 10 seconds.
- BB. Keep the standard-resolution metric and create an alarm with a period of 10 seconds.
- CC. Enable detailed monitoring on the instances that publish the metric.
- DD. Add the metric to a CloudWatch dashboard with a 10-second auto refresh.
Show the answer and explanation
Answer: A
- A. Right: Correct. High-resolution metrics are stored at one-second granularity and support high-resolution alarms with 10- or 30-second periods.
- B. Wrong: Standard-resolution metrics have one-minute granularity, so alarms on them cannot evaluate every 10 seconds.
- C. Wrong: Detailed monitoring changes how often EC2 sends its own metrics. It does not change custom metric resolution.
- D. Wrong: A dashboard refresh only redraws graphs. It does not evaluate the metric or send notifications.
Explanation
Custom metrics are standard resolution (one-minute granularity) unless published as high resolution (one-second granularity, set with StorageResolution in PutMetricData). Only high-resolution metrics support alarms with 10- or 30-second periods, and such alarms cost more.
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