SOA-C02 Question 91
Select 2A company hosts a web application on Amazon EC2 instances spread across multiple Availability Zones behind an Application Load Balancer. The application stores user-uploaded files in the instance store volumes. During an Availability Zone failure, users report they are unable to access their uploaded files. What changes should a SysOps Administrator implement to ensure fault tolerance for user-uploaded files?
- A
Move user-uploaded files to an Amazon Elastic File System (EFS) mounted across all EC2 instances.
- B
Use Amazon S3 to store user-uploaded files instead of the instance store volumes.
- C
Assign Elastic IP addresses to all EC2 instances for consistent access to files.
- D
Enable Multi-AZ deployments on the Application Load Balancer.
- E
Configure EC2 Auto Scaling to launch replacement instances in case of an Availability Zone failure.
Show answer and explanation
Correct answers: A, B
Explanation
To ensure fault tolerance for user-uploaded files, the storage solution must be resilient to Availability Zone failures. Instance store volumes are ephemeral and tied to their specific instances, making them unsuitable for fault-tolerant storage. Amazon EFS and Amazon S3 are both durable and highly available storage options that can be accessed across multiple Availability Zones, addressing the underlying issue.
- A. Correct.
Correct. Amazon EFS is a highly available and fault-tolerant file system that can be mounted across multiple EC2 instances in different Availability Zones, ensuring that files remain accessible even during an Availability Zone failure.
- B. Correct.
Correct. Amazon S3 is an object storage service designed for durability and availability. Moving user-uploaded files to S3 ensures they remain accessible regardless of EC2 instance or Availability Zone failures.
- C. Incorrect.
Incorrect. Elastic IP addresses provide static IPs for instances but do not address the issue of fault tolerance or file availability.
- D. Incorrect.
Incorrect. While enabling Multi-AZ on the Application Load Balancer improves load balancing fault tolerance, it does not solve the problem of file availability during an Availability Zone failure.
- E. Incorrect.
Incorrect. Auto Scaling helps replace failed instances, but it does not provide a solution for preserving or accessing the user-uploaded files stored on instance store volumes.