What is EFS?
Imagine you have a shared folder that multiple computers can access simultaneously, regardless of where they are. AWS Elastic File System (EFS) is exactly that, but for EC2 instances. It’s a fully managed, scalable, and high-availability network file system that allows multiple EC2 instances to read and write data simultaneously.
Unlike EBS, which is attached to a single EC2 instance, EFS can be mounted across multiple instances and Availability Zones (AZs). This makes it an excellent choice for workloads that require shared access to files.
Best Use Cases for EFS
- Content Management Systems (CMS) — Websites like WordPress need shared storage for media files.
- Web Hosting & File Serving — Websites and applications that serve static files.
- Big Data & Analytics — Distributed data processing and machine learning workflows.
- Media Processing — Video encoding and rendering where multiple instances access the same files.
- Application Data Sharing — Teams working with the same set of files across different servers.
- Backups & Disaster Recovery — Storing critical data that can be accessed from multiple locations.
🚨 Important Note: EFS only works with Linux-based AMIs because it uses the POSIX file system. If you need shared storage for Windows, consider FSx for Windows File Server.
Performance & Storage Classes
Performance Modes
EFS scales automatically to handle thousands of concurrent connections, but choosing the right mode ensures optimal performance:
- General Purpose — Low latency, best for CMS, web servers, and applications requiring quick file access.
- Max I/O — Higher latency but supports high throughput and parallel workloads, ideal for big data and media processing.
Throughput Modes
EFS offers different throughput modes based on workload demands:
- Bursting — Automatically scales throughput from 50 MiB/s per TB up to 100 MiB/s.
- Provisioned — Manually set throughput regardless of storage size, useful for workloads with consistent needs.
- Elastic — Automatically adjusts throughput based on real-time workload demands, ensuring efficiency.
Storage Classes
EFS helps optimize costs by offering different storage classes:
- Standard — For frequently accessed files with high availability.
- Infrequent Access (IA) — 50% cheaper than Standard, but retrieval incurs a fee, suitable for archived data.
- Archive — The lowest-cost option, ideal for rarely accessed files that need long-term storage.
💡 Pro Tip: Use Lifecycle Policies to automatically move files between storage classes and cut costs by up to 90%.
Availability & Durability
- Standard (Multi-AZ) — Data is replicated across multiple Availability Zones, making it highly available and resilient — great for production environments.
- One Zone — Data is stored in a single AZ, making it cheaper and ideal for development workloads or backups.
- Built-in Backup Support — EFS can automatically create backups to AWS Backup, ensuring data recovery in case of failures.
Cost Optimization with EFS
- Use Infrequent Access and Archive storage classes to reduce storage costs significantly.
- Enable lifecycle policies to automatically transition files to cheaper storage.
- Use One Zone storage when high availability isn’t a priority.
- Monitor usage with AWS Cost Explorer to optimize spending.
Summary
AWS Elastic File System (EFS) is a powerful, scalable, and durable storage solution that enables multiple EC2 instances to share file access seamlessly. It’s ideal for web hosting, content management, big data, and distributed applications. With the right performance modes, throughput settings, and storage classes, you can achieve cost savings of up to 90%.
TL;DR — Quick Takeaways:
✔ Managed network file system, accessible from multiple EC2 instances.
✔ Scales automatically, supporting thousands of concurrent connections.
✔ Multi-AZ (Standard) for production, One-Zone for dev & backups.
✔ Performance modes: General Purpose (low latency) vs. Max I/O (high throughput).
✔ Throughput modes: Bursting, Provisioned, Elastic (auto-scale).
✔ Storage classes: Standard, IA, Archive (up to 90% cost savings).
✔ POSIX-compliant — Works only with Linux-based AMIs.
✔ Use Lifecycle Policies to move files and cut storage costs.
Now you’re ready to leverage AWS EFS like a pro! 🚀