Amazon EFS for Shared Data in Auto Scaling Groups
Short answer
D Provision an Amazon Elastic File System (Amazon EFS) file system configured with General Purpose performance mode.
Question
Key Takeaways
The exam tests the distinction between block-level storage (EBS) and file-level storage (EFS), specifically highlighting EFS's ability to mount concurrently on many instances while maintaining high availability.
This question addresses the requirement for a highly available, shared file system across multiple EC2 instances without modifying application code. Amazon EFS is the correct solution as it provides scalable, network-attached storage compatible with Linux.
Common mistake: Candidates often select options involving custom NFS servers on EC2 or single AZ file systems because they underestimate the operational overhead of managing OS-level services versus using managed AWS storage.
Expert Analysis
Why the Answer Is Correct
Amazon EFS is designed specifically to provide a fully managed, elastic file system that can be mounted simultaneously on thousands of Amazon EC2 instances. It offers high availability by replicating data across multiple Availability Zones within a region. Since the question specifies a Linux environment and requires no significant code changes, EFS supports the standard NFSv4.1 protocol, allowing instances to mount the file system just like any local directory.
Why the Other Options Are Wrong
Option A describes building a custom NFS server on an EC2 instance; this creates a single point of failure and lacks built-in high availability unless complex clustering is implemented. Option B provisions an FSx for Windows File Server, which uses SMB protocols and is not natively supported by Linux clients without additional configuration, violating the 'no code changes' constraint. Option C suggests Provisioned IOPS SSDs but fails to describe how these volumes would be shared among multiple instances, as EBS volumes are typically attached to only one instance at a time.
Community Comment Notes
The community consensus strongly favors Option D, noting that EFS is the standard solution for shared data needs in auto-scaling groups. One commenter highlighted that EFS automatically scales and aligns perfectly with the requirements, while another pointed out that the question implies moving from a single volume to a shared file store, making EFS the logical migration path.
Exam Strategy
When you see keywords like 'shared data', 'multiple instances', 'Linux', and 'highly available', immediately consider Amazon EFS. Avoid solutions that require managing operating system services or custom networking unless explicitly required.
Frequently Asked Questions
Why can't we use a single EBS volume for multiple instances?
Does EFS require code changes for Linux applications?
Community Votes
100% of anonymous learners picked answer D. Votes are pick records left by other test-takers — they are not the verified answer.
Discussion 3 contributions
Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.
From public community threads 3
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JA2018 👍 2 Answered D3 reasons why I will choose Option D: #1 - Highly Available and Scalable: EFS is a managed file system designed for high availability and can automatically scale to accommodate the needs of multiple EC2 instances in an Auto Scaling group, which perfectly aligns with the company's requirement. # 2 - No code changes: Since EFS is a network file system, the application doesn't need significant code changes to access the data stored on it, as it can mount the file system like a local disk. #3 - General Purpose performance mode: This mode provides a balance between cost and performance, suitable for most application workloads.
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GOTJ 👍 1 Answered DIn my opinion, this question is not written properly, since it doesn't clearly states that the original EBS volume contains files within a filesystem. Changing "All instances require access to the data that is stored in the EBS volume" with "All instances require access to the FILES stored in the EBS volume" would do the trick. Assuming this, "D" should be the right answer.
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aragon_saa 👍 4 Answered DAnswer is D
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