Question 510
A T3 application server is configured in Unlimited mode. It holds CPU utilization above its baseline for many consecutive hours without the throttling seen in Standard mode, but the bill now contains CPU credit charges. Why?
Explanation
Correct Answer
With Unlimited, usage above baseline can draw surplus credits and incur the documented additional charge under the applicable averaging rules. Compare sustained workload price/performance with a nonburstable instance before assuming the T-family is the economical fit.
Incorrect Answers
The Unlimited mode permits prolonged bursts, but its billing treatment is not identical to free baseline entitlement. Sustained excess CPU can be charged.
EBS I/O charges and EC2 CPU-credit charges represent different metering dimensions. Disk IOPS does not relabel itself as compute surplus credits.
Health checks can replace unhealthy fleet members, not mint free credits. The Unlimited-mode surplus accounting is driven by the instance CPU use and credit rules.






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