Which storage solution should the solutions architect recommend?

Explanations:

Amazon DynamoDB is designed for high-frequency reads and writes but is better suited for smaller item sizes and key-value pairs. The requirement of handling 10 MB outputs per task and potentially hundreds of tasks concurrently may lead to complexity in item management and exceed DynamoDB’s item size limits and throughput considerations.

Amazon EFS with Provisioned Throughput mode provides scalable and elastic file storage that can handle high-frequency read and write operations efficiently. This option supports a high throughput that is required for handling large output sizes (10 MB per task) from multiple concurrent tasks, and the data can be accessed by all ECS instances easily.

While Amazon EFS with Bursting Throughput mode is cost-effective and can handle occasional high throughput, it is primarily designed for use cases with burstable performance. Given the requirement for consistent high-frequency reading and writing due to potentially hundreds of tasks, it may not meet the performance demands as effectively as Provisioned Throughput mode.

An Amazon EBS volume is limited to a single EC2 instance and does not provide the necessary shared access across all ECS cluster instances. This restriction would create bottlenecks and limit the scalability of the solution, making it unsuitable for the high-frequency read and write requirements across multiple tasks.