AWS Certified Solutions Architect – Associate (SAA-C03) — Question 865

A company is migrating its databases to Amazon RDS for PostgreSQL. The company is migrating its applications to Amazon EC2 instances. The company wants to optimize costs for long-running workloads.

Which solution will meet this requirement MOST cost-effectively?

Answer options

• A. Use On-Demand Instances for the Amazon RDS for PostgreSQL workloads. Purchase a 1 year Compute Savings Plan with the No Upfront option for the EC2 instances.
• B. Purchase Reserved Instances for a 1 year term with the No Upfront option for the Amazon RDS for PostgreSQL workloads. Purchase a 1 year EC2 Instance Savings Plan with the No Upfront option for the EC2 instances.
• C. Purchase Reserved Instances for a 1 year term with the Partial Upfront option for the Amazon RDS for PostgreSQL workloads. Purchase a 1 year EC2 Instance Savings Plan with the Partial Upfront option for the EC2 instances.
• D. Purchase Reserved Instances for a 3 year term with the All Upfront option for the Amazon RDS for PostgreSQL workloads. Purchase a 3 year EC2 Instance Savings Plan with the All Upfront option for the EC2 instances.

Correct answer: D

Explanation

For long-running, predictable workloads, committing to a 3-year term with the All Upfront payment option provides the maximum discount rate compared to shorter terms or partial/no upfront commitments. Options A, B, and C are less cost-effective because they rely on On-Demand pricing, 1-year terms, or payment structures that yield lower overall savings. Therefore, option D delivers the greatest cost optimization for sustained, long-term operations.