DEA-C01 Data Store Management Practice Question
A company needs to store files that are accessed by multiple EC2 instances in a VPC. The files must be concurrently accessible and durable. Which storage solution should the data engineer choose?
⚠ Common exam trap
Many exam-takers confuse Amazon EBS Multi-Attach with a general-purpose shared file system, but EBS Multi-Attach is limited to specific io1/io2 volumes, requires cluster-aware applications, and does not provide the POSIX file system semantics or cross-AZ durability that EFS offers.
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 Elastic File System (Amazon EFS)
Amazon EFS provides a fully managed, scalable, and elastic NFS file system that can be concurrently accessed by multiple EC2 instances across multiple Availability Zones. It is designed for high durability (11 nines of durability) and automatically replicates data across multiple AZs within a region, meeting the requirements for concurrent access and durability.
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 EC2 instance store
Why it's wrong here
Instance store is physically attached to a single EC2 host, so it cannot be concurrently mounted by multiple instances and its data is lost when the instance stops or terminates, failing both concurrency and durability. It is tempting for scratch data needing maximum IOPS, where ephemeral, single-instance storage is acceptable.
- ✗
Amazon Simple Storage Service (Amazon S3)
Why it's wrong here
S3 is object storage accessed over HTTPS endpoints rather than a shared POSIX file system, so applications expecting mounted file semantics need additional tooling. It is tempting because S3 is durable and concurrently accessible, and it would be correct for storing and retrieving objects such as backups, logs or datasets.
- ✗
Amazon Elastic Block Store (Amazon EBS)
Why it's wrong here
EBS volumes attach to a single EC2 instance in one Availability Zone and cannot be concurrently mounted read-write across multiple instances, failing the shared-access requirement. EBS is tempting because it offers low-latency block storage, and it would be correct for a single instance needing a boot volume or database disk.
- ✓
Amazon Elastic File System (Amazon EFS)
Why this is correct
Amazon EFS provides a shared, elastic NFS file system that many EC2 instances mount concurrently across Availability Zones, delivering the concurrent access and durability the scenario demands. Instance store and EBS volumes attach to a single instance, so they cannot satisfy the multi-instance requirement.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DEA-C01 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 DEA-C01 exam.