EFS (Elastic File System)

Question 1

What is EFS and how is it used

Answer 1

Amazon EFS is a scalable, fully managed file storage service. It is designed to provide simple, scalable, and highly available file storage for use with AWS cloud services and on-premises resources. You can create file systems of virtually any size and scale them up or down as needed without provisioning or managing storage capacity. Amazon EFS allows multiple Amazon EC2 instances to access and share the same file system concurrently. Amazon EFS stores data redundantly across multiple Availability Zones within a region to ensure durability and high availability. It automatically replicates data across multiple storage servers and Availability Zones, providing built-in data protection and fault tolerance.

Note: EFS is compatible with Linux based AMI (not Windows)
It uses security group to control access to it
You can only attach it to one VPC and only create one ENI (mount target) per AZ

Answer 2

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

General Purpose (default):

The General Purpose performance mode is designed to provide balanced performance for a wide range of workloads.
It offers low-latency access to files and scales throughput based on the size of the file system.

Max I/O:

The Max I/O performance mode is optimized for applications that require higher levels of aggregate throughput and operations per second (IOPS). It provides higher levels of throughput and IOPS compared to the General Purpose mode.

Question 3

What are EFS throughput modes

Answer 3

Amazon EFS offers three throughput modes: Bursting Throughput, Provisioned Throughput and Elastic Throughput

Bursting Throughput:

In Bursting Throughput mode, the file system’s throughput scales automatically based on the amount of data stored in the file system. 1TB = 50MiB/s + burst of up to 100MiB/s. Bursting Throughput mode is ideal for workloads with unpredictable or variable throughput

Provisioned Throughput:

In Provisioned Throughput mode, you specify the desired throughput rate for the file system, which remains constant regardless of the amount of data stored in the file system. Provisioned Throughput mode is suitable for workloads with consistent or predictable throughput requirements, where you need to ensure a certain level of performance regardless of file system size. 1GiB/s for 1TB storage

Elastic Throughput automatically scales throughput up or down based on your workloads. Up to 3GiB/s for reads and 1GiB/s for writes

Question 4

What are EFS Storage Classes

Answer 4

Storage Tiers:

Standard: For frequently accessed files
Infrequent access (EFS-IA): lower priced. You can enable with a lifecycle policy

Availability and durability
Regional: Multi-AZ, great for prod
One Zone: One AZ, great for dev, backup enabled by default

Question 5

How can you connect to EFS from other VPCs & On Premise servers

Answer 5

You can connect to EFS from another VPC using VPC peering

You can connect from an On-premise server using Direct Connect to the EFS mount target

Question 6

What are EFS access points and how can one use them

Answer 6

EFS Access Points enable you to define customized access configurations for accessing an EFS file system. You can create multiple access points for the same file system, each with its own set of permissions, file system root directory, and client mount options.

Question 7

Can you have cross-region replication on EFS

Answer 7

Yes