Elastic File Wonders: EFS Explained

What is Amazon EFS?

Amazon Elastic File System (EFS) is a fully managed, scalable, elastic file storage service for use with AWS Cloud services and on-premises resources.

It provides a shared file system accessible by multiple EC2 instances simultaneously, unlike EBS or Instance Store, which are limited to single-instance attachment.

Key features:

Fully managed: AWS handles scaling, patching, and maintenance.
Elastic storage: Automatically grows and shrinks as you add/remove files.
High availability: Data replicated across multiple Availability Zones.
Shared access: Multiple EC2 instances can mount the same file system.

Use Case Example (kaptaindevops)

kaptaindevops runs a web application across multiple EC2 instances in a cluster.

He uses EFS to store shared configuration files, logs, and media assets, ensuring all instances access the same files in real-time.

How EFS Differs from EBS and Instance Store

Feature	EFS	EBS	Instance Store
Persistence	Persistent	Persistent	Temporary
Shared Access	Multiple EC2 instances	Single EC2 instance	Single EC2 instance
Performance	Scales with demand, high throughput	SSD/HDD types, fixed IOPS	Very fast, local to host
Elasticity	Automatic scaling	Manual resizing	Fixed size at launch
Durability	Across AZs	Within AZ	Lost if instance stops/terminates
Use Case	Shared storage, media, logs, clusters	Databases, boot volumes, transactional data	Cache, scratch data, temp processing

EFS Storage Classes

Standard: For frequently accessed files.
Infrequent Access (IA): For files accessed less frequently.
Intelligent Tiering: Automatically moves files between Standard and IA based on access patterns.