SAP-C02 Practice Question: Accelerate Workload Migration and Modernization
A company is moving a legacy application that uses a shared file system to AWS. The application requires POSIX-compliant file storage that can be accessed by multiple EC2 instances simultaneously. Which AWS storage service should they use?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Amazon EFS
(Amazon EFS) is correct because it provides a scalable, POSIX-compliant NFS file system that can be accessed by multiple EC2 instances simultaneously. Option A (Amazon FSx for Windows File Server) uses SMB protocol and is not POSIX-compliant. Option C (Amazon EBS with Multi-Attach) only supports a limited number of instances and has specific constraints, and it is not a fully managed shared file system. Option D (Amazon S3) is object storage and does not provide POSIX compliance.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Amazon FSx for Windows File Server
Why it's wrong here
FSx for Windows File Server provides SMB shares with NTFS semantics, not POSIX permissions, so it cannot satisfy the stated POSIX requirement. It is tempting because it is a managed multi-AZ shared file system for concurrent EC2 access, and would be correct for Windows workloads needing SMB, ACLs and Active Directory integration.
- ✓
Amazon EFS
Why this is correct
Amazon EFS provides a POSIX-compliant, shared NFSv4 file system that multiple EC2 instances can mount concurrently across Availability Zones, satisfying the simultaneous multi-instance access requirement. Unlike EBS, which attaches to a single instance, EFS is purpose-built for shared file workloads, making it the appropriate fit for this legacy application.
- ✗
Amazon EBS with Multi-Attach
Why it's wrong here
EBS Multi-Attach permits a volume to attach to multiple Nitro instances in one AZ, but it exposes a raw block device, not a shared POSIX file system, so concurrent writes corrupt data. It is tempting as a multi-instance storage option, and suits clustered applications like Oracle RAC using cluster-aware software.
- ✗
Amazon S3
Why it's wrong here
Amazon S3 is object storage accessed through REST APIs, so it cannot be mounted as a POSIX-compliant shared file system across multiple EC2 instances. It is tempting because S3 offers durable, highly available shared access to data. Amazon EFS is the correct choice, providing NFS-based POSIX semantics for concurrent multi-instance mounting.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
Go deeper
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SAP-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SAP-C02 exam.