AWS Certified Solutions Architect - Associate

Explanation

Correct Answer: D - Implement an S3 Lifecycle policy that moves the objects from S3 Standard to S3 Standard-Infrequent Access (S3 Standard-IA) after 90 days.

Why this is the most cost-effective solution:

1. S3 Lifecycle policies are automated and cost-effective: Lifecycle policies automatically transition objects between storage classes based on age criteria, requiring no manual intervention or additional management overhead.

2. S3 Standard-IA is appropriate for infrequently accessed data: The problem states that downloads are infrequent for ringtones older than 90 days. S3 Standard-IA offers lower storage costs than S3 Standard while maintaining the same durability, availability, and performance characteristics.

3. Minimum object size requirement is met: The files are at least 128 KB in size, which meets the minimum object size requirement for S3 Standard-IA (128 KB).

4. Readily available access: S3 Standard-IA maintains millisecond access times, so files remain readily available for users when needed.

Analysis of other options:

A. Configure S3 Standard-IA storage for the initial storage tier: This is not optimal because newer ringtones (less than 90 days old) are likely accessed more frequently. Starting with S3 Standard-IA for all objects would incur unnecessary retrieval fees for frequently accessed newer content.

B. Move the files to S3 Intelligent-Tiering: While S3 Intelligent-Tiering can automatically move objects between access tiers, it's more expensive than using a simple lifecycle policy for predictable access patterns. The company knows that access patterns change at exactly 90 days, making a lifecycle policy more cost-effective.

C. Configure S3 inventory to manage objects: S3 inventory is a reporting tool, not an automation tool for moving objects. This would require building custom automation to move objects based on inventory reports, which is more complex and less efficient than using lifecycle policies.

Key AWS concepts:

• S3 Lifecycle policies: Automate transitioning objects between storage classes or expiring objects
• S3 Standard-IA: Designed for long-lived, infrequently accessed data with retrieval fees
• Cost optimization: Matching storage class to access patterns reduces costs while maintaining availability

This solution provides the best balance of automation, cost-effectiveness, and meeting the requirement of keeping files readily available.