EFS - Elastic File System

• It is a network based file system which can be mounted on Linux based instance
• Can be mounted to multiple instances at once
• EFS it is an implementation of the NFSv4 file system format
• EFS file systems can be mounted in a folder in Linux based operating systems
• EFS storage exists separately from the lifecycle of an EC2 instance
• It can be shared between many EC2 instances
• It is a private service, it can be mounted via mount targets inside a VPC. By default an EFS it is isolated to the VPC in which was provisioned
• EFS can be accessed outside of the VPC over hybrid networking: VPN or DX. EFS is a great tool for storage handling across multiple units of compute
• EFS is accessible for Lambda functions. Lambda has to be configured to use VPC networking in order to use EFS
• Mount targets: provide IP addresses in the range of the VPC. For HA we should provision mount targets in every availability zones present in a VPC
• EFS offers 2 performance modes:
  • General Purpose: ideal for latency sensitive use cases (it is the default)
  • Max I/O: can be used to scale to higher levels of aggregate throughput. Has higher latencies
• EFS offers 2 different throughput modes:
  • Bursting (default): works similar to EBS GP2 storage
  • Provisioned: we can specify throughput requirements independent of the size
• EFS offers 3 storage classes:
  • Standard: for data that is accessed and modified frequently
  • Infrequent Access (IA): cost-optimized storage class for data that is less frequently accessed (few times a quarter)
  • Archive: for data that is accessed a few times a year
• We can automatically move data between these 2 classes using lifecycle policies