Using Amazon EFS with Mobile App for Fast Content Delivery

Correct Answer: C, E.

Option A is INCORRECT because Amazon EFS data is distributed across multiple Availability Zones (AZs), providing a high durability and availability level.

Option B is INCORRECT because EFS supports two throughput modes to choose from for your file system, Bursting Throughput, and Provisioned Throughput.

With Bursting Throughput mode, throughput on Amazon EFS scales as your file system grows.

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.

To accommodate this, EFS is designed to burst to high throughput levels for periods of time.

Option C is CORRECT because EFS serves as a local file system and is not directly accessible.

All the read/write operations have to be done via the EC2 with which it is attached.

Option D is INCORRECT because EFS provides both in-transit and at-rest encryption options using the AWS KMS service.

Option E is CORRECT because EFS uses a credit system to determine when file systems can burst.

Each file system earns credits over time at a baseline rate determined by the size of the file system and uses credits whenever it reads or writes data.

So if you have proportionally high read/write compared to overall data, you may face the burst capacity issues and opt to the Throughput Provisioned Mode.

Specifying Throughput with Provisioned Mode.

AWS EFS supports Provisioned Throughput mode, which allows applications configured to provision the throughput irrespective of the data stored inside the file system.

This means applications with higher throughput requirements can use this mode to achieve higher performance.

Keep in mind that Provisioned Throughput is billed separately from the data storage depending on the capacity.

The correct statements regarding EFS when working with the application are: B. The throughput of EFS increases with storage capacity, so the download is always faster with more data. E. EFS performance is dependent on storage size. Under heavy load such as when the throughput limit exceeds 1024 MiB/s, EFS may start to throttle unexpectedly.

Explanation: Amazon Elastic File System (EFS) is a scalable, fully managed, cloud-based NFS file system for Linux-based workloads. It can be used to store and share files across multiple instances in a scalable and highly available way. When working with the mobile application, EFS can be used as a shared file system to store and deliver images and videos to users.

Option A is incorrect. EFS is highly available and automatically replicates data across multiple Availability Zones (AZs) within a region to provide durability and availability. However, it is recommended to periodically backup the data to ensure no data is lost.

Option B is correct. The throughput of EFS is directly proportional to the amount of data stored in it. This means that the more data stored in EFS, the higher the throughput. This is because EFS automatically scales the throughput based on the size of the file system.

Option C is incorrect. EFS is mounted in the local file system of EC2 instances, but the file system is accessible through NFS, which means that the application can read and write files to the file system just like a local file system.

Option D is incorrect. EFS provides encryption in transit using Transport Layer Security (TLS) and at rest using encryption keys managed by AWS Key Management Service (KMS). This means that data stored in EFS can be encrypted both in transit and at rest.

Option E is correct. EFS performance is dependent on the amount of data stored in it. Under heavy load, such as when the throughput limit exceeds 1024 MiB/s, EFS may start to throttle unexpectedly. This is because EFS provides throughput on a per-byte basis, and if a file system exceeds its allowed throughput, EFS may throttle the throughput to ensure that other file systems in the same Availability Zone are not affected.