A company has a website that enables users to upload videos. Company policy states the uploaded videos must be analyzed for restricted content. An uploaded video is placed in Amazon S3, and a…

Using Reserved Instances (RIs) for the sporadic video analysis workload is less cost-effective than Spot Instances, as RIs are designed for predictable, steady-state usage, and would incur costs even during periods of low demand, rather than dynamically scaling down like Spot with Auto Scaling.

Keeping the website on T2 instances is cost-effective for general web serving. For the compute-intensive and sporadic video analysis, migrating to C5 compute-optimized instances provides better performance per dollar. Utilizing Amazon EC2 Spot Instances for additional capacity drastically reduces costs for the flexible, fault-tolerant analysis workload, and configuring Auto Scaling based on SQS queue depth automatically provisions and deprovisions instances as demand fluctuates, optimizing costs and eliminating manual intervention.

Migrating the website to C4 instances (compute-optimized) might be an overprovision for a general "website" and potentially increase its cost unnecessarily, as T2 instances could be sufficient. Also, C5 instances generally offer better price-performance than C4 for compute-intensive tasks.

Migrating the website to R4 instances (memory-optimized) is likely inappropriate and more expensive for a general "website" workload, as is using R4 instances for a "compute-intensive" task unless it also has very high memory requirements, which are not specified.