Skip to content

EFS

Links: 101 AWS SAA Index

EFS

  • It is a managed and shared NFS (network file system)
  • It can be mounted on many EC2 across AZs (shared component). EBS was locked in a single AZ. This means EFS is a regional service.
  • It is quite expensive as compared to EBS volumes. It is 3 times the cost of a gp2 drive.
You pay for only what you use. In EBS volumes you pay for the whole volume even though you are not using it.
  • With Amazon EFS, you pay only for the resources that you use. The EFS Standard Storage pricing is $0.30 per GB per month. Therefore the cost for storing the test file (1GB) on EFS is $0.30 for the month.
  • For EBS General Purpose SSD (gp2) volumes, the charges are $0.10 per GB-month of provisioned storage. Therefore, for a provisioned storage of 100GB for this use case, the monthly cost on EBS is $0.10*100 = $10. This cost is irrespective of how much storage is actually consumed by the test file(1 GB).
  • For S3 Standard storage, the pricing is $0.023 per GB per month. Therefore, the monthly storage cost on S3 for the test file is $0.023.
  • It is scalable, highly available POSIX compliant file system.
  • Whenever you see terms like POSIX, concurrent connection from multiple EC2 instances, low latency file operations in questions go for EFS.
If you don't require concurrent accessible storage then always go for EBS volumes.

EBS offers less latency than EFS.

  • Don't modify permissions of root directory, create a subdirectory for each user.
It is not block storage like EBS and Instance stores. It is a file based storage system.
  • Only works with linux based AMIs.
  • We use security groups to control access to EFS. If you want more security POSIX permissions can be used to restrict host from hosts based on users and groups.
  • Use an lAM policy to control access for clients who can mount your file system with the required permissions.
  • Data is encrypted in transit and at rest.
  • You can connect to Amazon EFS file systems from EC2 instances in other AWS regions using an inter-region VPC peering connection, and from on-premises servers using an AWS VPN connection
  • EFS can scale to petabyte storage automatically and support 1000 NFS clients concurrently.

Different options for EFS

Storage tiers

  • If the file has not been accessed for N days (generally 7) then it will be moved from standard to infrequent access
  • Different storage tiers are:
    • Standard: For frequently accessed file.
    • Infrequent access (EFS - IA): cost to retrieve, lower cost to store.
      • To use EFS-IA we must use a lifecycle policy.

Availability and durability

  • Standard: Multi AZ, great for prod.
  • One Zone: Only in 1 AZ, dev, we get 90% cost savings.

Performance Mode

  • Set at the time of EFS creation.
  • Defaults to General Purpose.
  • Different performance modes are:
    • General purpose: latency sensitive use cases. Web servers, CMS.
    • Max IO: High latency.
      • Max I/O performance mode is used to scale to higher levels of aggregate throughput and operations per second. This scaling is done with a tradeoff of slightly higher latencies for file metadata operations. Highly parallelised applications and workloads, such as big data analysis, media processing, and genomic analysis, can benefit from this mode.
      • Suitable for high frequency read and write operations.

Throughput mode

  • Defaults to bursting
  • Different throughput modes are:
    • Bursting: File-based workloads are typically spiky, driving high levels of throughput for short periods of time, and low levels of throughput the rest of the time
    • Provisioned: high frequency reading and writing, better performance than bursting.
Bursting vs Provisioned

By default, AWS recommends that you run your application in the Bursting Throughput mode. But, if you're planning to migrate large amounts of data into your file system, consider switching to Provisioned Throughput mode.

Last updated: 2023-03-03