AWS Certified Cloud Practitioner — Question 880

A company has a database server that is always running. The company hosts the server on Amazon EC2 instances. The instance sizes are suitable for the workload. The workload will run for 1 year.
Which EC2 instance purchasing option will meet these requirements MOST cost-effectively?

Answer options

• A. Standard Reserved Instances
• B. On-Demand Instances
• C. Spot Instances
• D. Convertible Reserved Instances

Correct answer: A

Explanation

Standard Reserved Instances offer the highest discount for steady-state workloads with a committed term of 1 year when no changes to the instance family are expected. Convertible Reserved Instances provide less of a discount than Standard RIs, while On-Demand Instances are much more expensive for continuous workloads. Spot Instances are not suitable for an always-running database because they can be interrupted by AWS with short notice.