AWS Certified Solutions Architect Professional SAP-C02 Practice Question

The correct answer is to purchase a Compute Savings Plan for the stable backend fleet and use Spot Instances for the video transcoding platform.

• Compute Savings Plans are the ideal choice for the application backend because they provide significant discounts (up to 66%) and are highly flexible. They automatically apply to EC2 instance usage regardless of instance family, size, AWS Region, OS, or tenancy. This perfectly matches the requirement for a stable workload that is distributed across various instance families and regions, simplifying management while maximizing savings.

• Spot Instances are the best fit for the video transcoding platform. This workload is fault-tolerant and can handle interruptions, which is the primary requirement for using Spot Instances. In exchange, Spot Instances offer the deepest discounts, up to 90% off On-Demand prices, making them the most cost-effective option for this type of batch processing job.

Incorrect options explained:

• Purchasing EC2 Instance Savings Plans would be suboptimal. While they offer a slightly higher discount (up to 72%), they lock you into a specific instance family and region. This would require purchasing and managing multiple plans for this workload, adding complexity and reducing flexibility compared to a single Compute Savings Plan.
• Using Convertible Reserved Instances is a plausible but less efficient strategy. While they offer flexibility to change instance families, managing these exchanges across multiple regions is a manual process that adds operational overhead. Compute Savings Plans provide similar flexibility but apply discounts automatically, making them a more modern and efficient solution for this scenario.
• Relying solely on On-Demand pricing for the transcoding workload completely misses the significant cost-saving opportunity presented by Spot Instances. For workloads that are interruptible, using On-Demand is unnecessarily expensive.