This solution provides the largest cost reduction by addressing both storage and compute costs effectively. Storing the 200 TB of data in Amazon S3 is significantly cheaper than keeping it on a continuously running, self-managed file system on EC2. S3 Intelligent-Tiering further optimizes storage costs by automatically moving data to lower-cost tiers when it's not accessed. For the monthly 72-hour job, creating an Amazon FSx for Lustre file system on-demand provides the required high performance. Using "lazy loading" is key, as it only loads data from S3 as it is read by the application. Since the job only reads a subset of the data, this minimizes data transfer costs and the required size of the FSx file system, maximizing savings. The file system is deleted after the job, eliminating all associated costs.

B. Amazon EBS Multi-Attach provides shared block storage, not a managed file system. It would require a complex, self-managed clustered file system on top and would be significantly more expensive than an S3-backed solution.
C. This option is less cost-effective than option A. S3 Standard is more expensive for infrequently accessed data than S3 Intelligent-Tiering. Batch loading would inefficiently load all 200 TB into FSx, increasing costs and startup time.
D. AWS Storage Gateway (File Gateway) is not designed for high-performance, parallel access from hundreds of compute instances. It would become a performance bottleneck and is not suitable for this data-intensive HPC-style workload. ---
References:
1. Amazon FSx for Lustre - Data Repositories: The AWS documentation explicitly describes using S3 as a data repository and the benefits of lazy loading. It states, "When you link your file system to an S3 bucket, you can choose to load data from S3 as it's accessed... This approach is known as lazy loading... Lazy loading is useful for workloads where you don't know which files will be accessed." Source: AWS Documentation, Amazon FSx for Lustre User Guide, "Using data repositories with Amazon FSx for Lustre", Section: "Lazy load".
2. Amazon S3 Storage Classes - Intelligent-Tiering: The official documentation highlights the cost-saving mechanism of S3 Intelligent-Tiering for data with changing or unknown access patterns, which is ideal for a monthly job. "The S3 Intelligent-Tiering storage class is designed to optimize storage costs by automatically moving data to the most cost-effective access tier when access patterns change." Source: AWS Documentation, Amazon S3 User Guide, "Amazon S3 storage classes", Section: "S3 Intelligent-Tiering".
3. Amazon EBS Multi-Attach: The documentation clarifies that Multi-Attach provides shared block-level access but does not manage file-level concurrent access. "Multi-Attach enabled volumes do not support I/O fencing... Applications and operating systems must provide a mechanism to manage concurrent write operations from multiple attached instances." This confirms it is not a ready-to-use shared file system. Source: AWS Documentation, Amazon EC2 User Guide for Linux Instances, "Amazon EBS volumes", Section: "Attach a volume to multiple instances with Amazon EBS Multi-Attach".
4. AWS Storage Gateway - What is File Gateway?: The documentation describes File Gateway's primary use case as providing on-premises applications with low-latency access to data in S3, not as a high-performance file system for a large EC2 cluster. Source: AWS Documentation, AWS Storage Gateway User Guide, "What is AWS Storage Gateway?", Section: "File Gateway".