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Elastic File System

EFS is a scalable, managed Network Attached Storage (NAS) service offered by Amazon Web Services. It is designed to provide shared file storage that can be easily accessed by multiple Amazon EC2 instances, making it suitable for a wide range of applications, including content management, web serving, and data sharing. EFS offers automatic scalability, high availability, and a simple, pay-as-you-go pricing model. It is an ideal choice for workloads that require shared file storage across multiple servers or applications in an AWS environment.

Is EFS a NTFS?

No, EFS (Elastic File System) in AWS is not an NTFS (New Technology File System). NTFS is a file system used primarily in Windows operating systems, whereas EFS is a managed cloud-based file storage service provided by AWS.

EFS provides its own file system that is accessible from multiple EC2 instances and on-premises servers, supporting various operating systems like Linux and Windows. The specific file system used by EFS is not publicly disclosed, but it is designed to be compatible with different operating systems and applications, making it suitable for a wide range of workloads.

Encryptions​

Amazon EFS supports two forms of encryption for file systems, encryption of data in transit and encryption at rest.

  • You can enable encryption of data in transit when you mount the file system.
  • You can only enable encryption of data at rest when creating an Amazon EFS file system.

Performance​

Performance modes​

Amazon EFS offers two performance modes, General Purpose and Max I/O:

  • General Purpose mode
  • Max I/O mode is designed for highly parallelized workloads that can tolerate higher latencies than the General Purpose mode.
When to use which?

If the PercentIOLimit percentage returned in CloudWatch was at or near 100 percent for a significant amount of time during the test, your application should use the Max I/O performance mode. Otherwise, it should use the default General Purpose mode.

Throughput modes​

A file system's throughput mode determines the throughput available to your file system. Amazon EFS offers three throughput modes: Elastic, Provisioned, and Bursting.

  • Elastic Throughput (recommended) – Use the default Elastic Throughput when you have spiky or unpredictable workloads and performance requirements that are difficult to forecast.
  • Provisioned Throughput mode is available for applications with high throughput to storage (MiB/s per TiB) ratios, or with requirements greater than those allowed by the Bursting Throughput mode.
  • With Bursting Throughput mode, a file system's throughput scales as the amount of data stored in the standard storage class grows.

EFS access points vs EFS mount targets​

TL;DR - EFS Access Points allow for granular access control to specific directories within an EFS file system, while EFS Mount Targets provide access to the** entire file system within a subnet**

EFS Access Points and EFS Mount Targets in AWS are both used to facilitate access to Amazon EFS from EC2 instances, but they serve different purposes and have distinct use cases.

  • Mount targets in Amazon EFS are deployed within specific availability zones and provide PrivateIPs for mounting the EFS filesystem.
    • [Number and Association] You typically have at least one mount target per subnet for accessing an EFS file system
  • Access Points are like sub-directories in EFS that allow fine-grained access control. They enable sharing EFS across multiple resources and provide customizable permissions at the sub-directory level(a.k.a, accesspoint).
    • [Number and Association] You can create multiple access points per file system, each with its distinct permissions.

The EFS mount helper​

The EFS mount helper is a tool or utility that simplifies the process of mounting an Amazon EFS file system onto an Amazon EC2 instance. The mount helper is pre-installed on Amazon Linux-based EC2 instances, and it's also available for other Linux distributions.

Using the EFS mount helper, you have the following options for mounting your Amazon EFS file system:

  • You can mount with IAM authorization
  • Auto-mounting when an EC2 instance reboots
  • Mounting on supported EC2 instances
  • Mounting with Amazon EFS access points
  • Mounting with an on-premise Linux client
  • Mounting a file system when a new EC2 instance launches

Some metrics​

  • Use ClientConnections to track the number of Amazon EC2 instances that are connected to a file system
  • You can see your burst credit balance by monitoring the BurstCreditBalance metric for your file system.
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