What is AWS EFS (Elastic File System) ?

AWS EFS (Elastic File System) is managed NFS (network file system) that can be mounted on many EC2.

  • AWS EFS works with EC2 instances in multi-AZ.
  • It is highly available, scalable, expensive (3x gp2), pay per use.
  • Use cases: content management, web serving, data sharing, WordPress.
  • Uses NFSv4.1protocol
  • Uses security group to control access to EFS
  • Compatible with Linux based AMI (not Windows)
  • Encryption at rest using KMS
  • POSIX file system (~Linux) that has a standard file API
  • File system scales automatically, pay-per-use, no capacity planning!

AWS EFS – Performance & Storage Classes

EFS Scale:

  • 1000s of concurrent NFS clients, 10 GB+ /s throughput
  • Grow to Petabyte-scale network file system, automatically

Performance mode (set at EFS creation time):

  • General purpose (default): latency-sensitive use cases (web server, CMS, etc…)
  • Max I/O – higher latency, throughput, highly parallel (big data, media processing)

Storage Tiers (lifecycle management feature – move file after N days):

  • Standard: for frequently accessed files
  • Infrequent access (EFS-IA): cost to retrieve files, lower price to store



EBS volumes:

can be attached to only one instance at a time

are locked at the Availability Zone (AZ) level

gp2: IO increases if the disk size increases

io1: can increase IO independently

To migrate an EBS volume across AZ

Take a snapshot

Restore the snapshot to another AZ

EBS backups use IO and you shouldn’t run them while your application is handling a lot of traffic

Root EBS Volumes of instances get terminated by default if the EC2 instance gets terminated. (you can disable that)

Mounting 100s of instances across AZ

EFS share website files (WordPress)

Only for Linux Instances (POSIX)

EFS has a higher price point than EBS

Can leverage EFS-IA for cost savings

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