Your company recently launched a mobile application that allows users to take pictures of what they are eating daily, share with others, and get feedback to maintain a healthy diet routine. These pictures are stored in S3 and served via the CloudFront. The CEO of the company thinks the storage is not well optimized by looking at the bill. He has asked to generate the access log reports and shift the images to different storage if they are not frequently used. It is not very clear which images will be accessed frequently, but as per the past data analysis, the usage becomes low after the initial 3-4 weeks. Please select the best option to optimize the cost and also maintain accessibility.

Answer options:

A.Use CloudFront Edge Locations and enable access logs. It will automatically optimize the storage cache based on the access pattern.
B.Apply Lifecycle event to migrate from S3 Standard to Glacier after 3 weeks.
C.Create an elastic load balancer, point to the CloudFront distribution, and enable the Access Logs. Use Kinesis to process the logs and shift the images to S3 Infrequent Access based on low usage.
D.Store the images with S3 Intelligent Tier. It will automatically select the best storage class depending on the access pattern.
E.Store the images on EC2 EBS and serve it from there. EBS is highly optimized and cheap compared to S3. Put a lifecycle event to shift the unused images to S3 after 30 days.
 

Correct Answer: D
Option A is INCORRECT because the CloudFront is used to deliver the images to end users to reduce the latency lag. Edge Locations work as caching servers, and it saves the images based on the frequency of use. However, CloudFront still loads the content from the origin S3 Bucket.
Option B is INCORRECT because migrating the images to Glacier will make it almost inaccessible after 3 weeks. Glacier retrieval time is between 3-5 hours, and per the requirement, the application still needs to maintain accessibility.
Option C is INCORRECT because the CloudFront already geo-distributes the load and putting an elastic load balancer in front of it is not viable.
Option D is CORRECT because S3 Intelligent Tier automatically shifts content between Standard and Infrequent Access tier based on the usage pattern. If the content is not used for 30 consecutive days, it will automatically be moved to the Infrequent Access tier. Upon use, it will be transferred back to the Standard tier without any additional cost.
Option E is INCORRECT because serving images from EBS is not very scalable as compared to S3 storage. There is no lifecycle event for EBS volumes.
Source: https://aws.amazon.com/s3/storage-classes/