Amazon EFS (Elastic File System)
🔹 Definition:
A serverless, elastic, NFS-based file storage service that can be mounted on multiple EC2 instances (Linux-based).
- Managed shared file system (POSIX-compliant).
- Automatically scales up/down with usage.
Key Features
- Fully managed → No provisioning required.
- Elastic → Grows/shrinks automatically with data.
- Shared access → Multiple EC2s (thousands) can mount the same EFS.
- Durability → Data stored across multiple AZs (high availability).
- Access via NFSv4 protocol.
- Lifecycle management → Automatically move cold files to cheaper storage (EFS-IA).
Performance Modes
- General Purpose → Default, low latency (web servers, dev/test).
- Max I/O → Higher throughput, higher latency (big data, analytics).
Storage Classes
- Standard (EFS Standard) → Multi-AZ, highly durable.
- Infrequent Access (EFS-IA) → Lower-cost for rarely accessed files.
EFS vs EBS vs S3
| Feature | EFS | EBS | S3 |
|---|---|---|---|
| Type | Shared file system | Block storage | Object storage |
| Access | Multiple EC2s (multi-AZ) | One EC2 (single AZ) | Global, via HTTP API |
| Protocol | NFS | Attached volume | REST API |
| Scaling | Auto | Fixed size | Virtually unlimited |
| Durability | Across AZs | Single AZ (unless snapshot) | 11 9’s across regions |
Use Cases
- Web/app servers needing shared storage.
- Content management systems.
- Big data analytics.
- Container storage for ECS/EKS.
- Home directories for user apps.
