An application on EC2 produces gigabytes of data daily. Files are rarely accessed but must be retrievable within minutes during the first year. Files must be retained for 7 years. What is the most cost-effective storage strategy?

The most cost-effective solution is to use S3 Glacier Instant Retrieval initially because it offers low-cost storage with retrieval in milliseconds, meeting the "retrievable within minutes" requirement for the first year. After one year, an S3 Lifecycle rule transitions the data to S3 Glacier Deep Archive, which is the lowest-cost storage class for long-term archival (7 years) where retrieval times of up to 12 hours are acceptable. Storing in S3 Standard is more expensive than necessary for rarely accessed data. Using EBS volumes and snapshots for gigabytes of daily data is not cost-effective for long-term archival and is more complex to manage than S3. EFS is a file system for shared access, not optimized for low-cost, rarely accessed archival storage, and EFS Standard-Infrequent Access is still more expensive than S3 Glacier classes for this use case.