Quick Answer
The answer is Amazon EFS, as it is the only AWS storage service that provides a fully managed, POSIX-compliant NFS file system designed for concurrent access from multiple EC2 instances while delivering strong consistency across all reads and writes. This strong consistency guarantee means that any write operation is immediately visible to all subsequent reads from any connected instance, which is critical for workloads like content management systems or shared databases that cannot tolerate stale data. On the AWS Certified Solutions Architect Professional SAP-C02 exam, this question tests your ability to distinguish between block, file, and object storage use cases, with a common trap being the mistaken belief that EBS Multi-Attach (which is limited to io1/io2 volumes and specific instance types) can serve as a general-purpose shared file system. Remember the memory tip: “EFS for Every File System” — if you need multiple EC2 instances to share files with strong consistency, EFS is the default choice, not EBS or S3.
This SAP-C02 practice question tests your understanding of continuous improvement for existing solutions. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company is migrating an on-premises application to AWS. The application requires persistent shared storage that can be accessed by multiple EC2 instances simultaneously with strong consistency. Which AWS storage solution should the company use?
Amazon S3 with S3 File Gateway.
Why wrong: File Gateway provides a file interface but consistency is eventual for S3.
Amazon S3 Glacier Deep Archive.
Why wrong: Glacier is for archival, not active shared storage.
Amazon EBS with Multi-Attach enabled.
Why wrong: Multi-Attach is limited to a few instance types and has consistency caveats.
Amazon EFS
EFS provides a POSIX file system with strong consistency across instances.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Amazon EFS
Option D is correct because Amazon EFS provides a fully managed NFS file system that can be mounted by multiple EC2 instances with strong consistency. Option A is wrong because EBS volumes can only be attached to one instance at a time (multi-attach is limited). Option B is wrong because S3 is object storage, not a file system. Option C is wrong because S3 Glacier is for archival.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Amazon S3 with S3 File Gateway.
Why it's wrong here
File Gateway provides a file interface but consistency is eventual for S3.
Amazon S3 Glacier Deep Archive.
Why it's wrong here
Glacier is for archival, not active shared storage.
Amazon EBS with Multi-Attach enabled.
Why it's wrong here
Multi-Attach is limited to a few instance types and has consistency caveats.
Amazon EFS
Why this is correct
EFS provides a POSIX file system with strong consistency across instances.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Identify which SAP-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Continuous Improvement for Existing Solutions — study guide chapter
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FAQ
Continuous Improvement for Existing Solutions — This question tests Continuous Improvement for Existing Solutions — Read the scenario before looking for a memorised answer..
The correct answer is: Amazon EFS — Option D is correct because Amazon EFS provides a fully managed NFS file system that can be mounted by multiple EC2 instances with strong consistency. Option A is wrong because EBS volumes can only be attached to one instance at a time (multi-attach is limited). Option B is wrong because S3 is object storage, not a file system. Option C is wrong because S3 Glacier is for archival.
Identify which SAP-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 20, 2026
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.
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