What is EFS?
It stands for Amazone Elastic Fil Systm, meaning a file storage service for Amazone Compute Cloud (Amazone EC2) instances. Amazone EFS is easy to use and provides a simple I/F that enables you to create and configure file systems quickly and easily. With Amazone EFS, storage capacity is elastic, growing and shrinking automatically as you add and remove files, so your applications have the storage they need, when they need it.
Features
Supports the Network File System version4 protocol
Pay for the storage you use — no pre-provisioning
Scale up to the petabytes
Supports thousands of concurrent NFS connections
Stored across multiple AZ’s within a region
Read After Write Consistency just lik S3
Block Based Storage, not object based storage.
Use Case
One load balancer routing request to two running instances with apache web server in multiple Available Zones within a region, if you mount a EFS to the two instances, you can serve the request with only just one file in EFS, no need to duplicately copying the same files in each instances.
