Q52 — AWS SAA-C03 Ch.2

Question 52 of 65 | ← Chapter 2

Q117. A company wants to reduce the cost of its existing three-tier web architecture. The web, application, and database servers are running on Amazon EC2 instances for the development, test, and production environments. The EC2 instances average 30% CPU utilization during peak hours and 10% CPU utilization during non-peak hours.The production EC2instances run 24 hours a day. The development and test EC2 instances run for at least 8 hours each day. The company plans to implement automation to stop the development and test EC2 instances when they are not in use.Which EC2 instance purchasing solution will meet the company's requirements MOST cost-effectively?

Correct Answer: B. Use Reserved Instances for the production EC2 instances Use On-Demand Instances for the development and test EC2 instances.

Explanation

The EC2 instance purchasing solution that will meet the company's requirements MOST cost-effectively is B. Use Reserved Instances for the production EC2 instances and use On-Demand Instances for the development and test EC2 instances. Reserved Instances (RIs) provide significant cost savings when compared to On-Demand Instances. RIs require an upfront payment, but offer a discounted hourly rate over the life of the reservation. They are most cost-effective for workloads that run continuously, like the production environment described in this scenario. On-Demand Instances do not require an upfront payment or long-term commitment, but have a higher hourly rate than RIs. They are well-suited for workloads with unpredictable compute requirements, such as the development and test environments in this scenario. Using Spot Instances or Spot Blocks may offer even greater cost savings than On-Demand Instances, but these instances can be interrupted at any time if the demand for capacity increases. In the case of Spot Blocks, they have fixed start and end times which might not align with the actual usage patterns in this scenario. Therefore, using On-Demand Instances for development and test and Reserved Instances for production is the best option in this scenario.