Amazon Elastic File System (EFS) Overview

1. What is Amazon EFS?

Amazon Elastic File System (EFS) is a managed NFS (Network File System) that allows multiple EC2 instances to access the same file system across multiple Availability Zones (AZs).

Key Features:

✅ Highly available – Spans multiple AZs for disaster resilience.

✅ Scalable – Automatically expands and shrinks as needed.

✅ Expensive – 3x the cost of GP2 EBS volumes, but pay-per-use (no pre-provisioning).

✅ Supports Linux only – Not compatible with Windows-based AMIs.

✅ Secure – Uses security groups for access control and KMS encryption for data protection.

Use Cases:

• Content management systems (CMS)
• Web hosting (e.g., WordPress)
• Data sharing between instances
• Big data processing and analytics

2. How EFS Works

• An EFS file system is created within a VPC and protected by security groups.
• Multiple EC2 instances across different AZs can mount the file system simultaneously.
• Data is stored using NFS protocol and follows POSIX compliance, making it a standard Linux filesystem.
• No need for capacity planning – storage scales dynamically.