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AWS Certified Solutions Architect - Associate Exam Question Walkthrough
Understand how to choose the right file system for EC2 instances with this AWS SAA-C03 exam question walkthrough.
Multiple Linux EC2 instances across AZs need concurrent access to the same shared file system that scales automatically. Which service should be used?
A. Amazon EBS attached to one instance
B. Amazon EFS
C. Instance store volumes
D. Amazon S3 Glacier
Think before you scroll
Consider the requirements: multiple instances, concurrent access, and auto-scaling. Not all services are designed for shared access across Availability Zones (AZs).
The answer
The correct option is B. Amazon EFS. Amazon Elastic File System (EFS) allows multiple EC2 instances to mount the same file system concurrently across different AZs, providing the scalability needed.
Why the other options lose
A. Amazon EBS attached to one instance: Amazon Elastic Block Store (EBS) is designed for single-instance attachment. While it provides persistent storage, it cannot be shared across multiple instances in different AZs. This disqualifies it for the requirement of concurrent access.
C. Instance store volumes: These volumes provide temporary storage directly attached to the host EC2 instance. They cannot be shared among instances and do not persist beyond the instance lifecycle, making them unsuitable for this scenario.
D. Amazon S3 Glacier: This service is meant for archival storage and retrieval of data. It is not designed for file system access and does not support concurrent access from EC2 instances, which rules it out entirely for this need.
The concept behind it
The principle at play here is understanding the different storage solutions AWS offers. Amazon EFS is specifically tailored for scenarios requiring shared file systems across multiple instances, while EBS and instance stores are more limited in their access and use cases. S3 Glacier serves a completely different purpose, focusing on long-term data archiving.
Exam trap to remember
Remember: for concurrent access across multiple instances, EFS is the go-to solution. EBS is for single-instance attachment, while instance stores are temporary and non-shareable.