AWS Certified Cloud Practitioner (CLF-C02)Cloud Technology and ServicesMedium
A developer wants an AWS storage service that multiple EC2 instances across different Availability Zones can mount and read/write simultaneously using standard file system protocols. Which service should they use?
- AAmazon EFS
- BInstance Store
- CAmazon EBS
- DAmazon S3
Show answer & explanationAnswer & explanation
Correct answer: A. Amazon EFS
Amazon EFS is a fully managed, scalable NFS file system that can be mounted concurrently by multiple EC2 instances across multiple Availability Zones, providing shared file storage.
Why the other options are wrong
- B. Instance Store is ephemeral, local storage tied to a single instance and lost on stop/terminate.
- C. EBS volumes attach to only one instance at a time (except Multi-Attach for specific volume types within a single AZ).
- D. S3 is object storage accessed via API/HTTP, not a mountable file system for POSIX-style access.
Amazon EFS
A managed, elastic NFS file system that can be concurrently mounted by many EC2 instances across multiple AZs.
- Uses NFS protocol
- Scales automatically with usage
- Supports multi-AZ concurrent access
Memory trick: EFS = Everyone's File Share