Practice Exam AWS Certified Solutions Architect Professional

Based on the scenario provided, the correct solution to implement reliability and scalability in video processing workloads on AWS involves the following components and architecture:

1. S3 as a Source of Truth: Instead of using EFS, which is block storage for use with Amazon EC2 instances, you would upload video files directly to an S3 bucket. S3 offers high durability, availability, and scalability, and is well-suited for storing large files like videos.

2. S3 Event Notifications: Configure the S3 bucket to emit events when a new file is uploaded. This triggers a Lambda function without the need for an API Gateway, as Lambda can be invoked directly by S3.

3. Lambda Function: The Lambda function processes the uploaded video file and stores the processed files in another S3 bucket. After processing, the Lambda function sends a message to an SQS queue with details about the video processing instructions and a link to the processed file(s).

4. Amazon Simple Queue Service (SQS): The video processing application reads messages from the SQS queue. This decouples the production of video files from their processing, ensuring that even if the processing system is temporarily overloaded, incoming video files will not be lost and can be processed later.

5. Auto Scaling Group with SQS Queue Depth Scaling: The size of the Auto Scaling group for video processing instances can be automatically adjusted based on the depth of messages in the SQS queue. This ensures that resources are scaled up or down based on demand, optimizing costs and performance.

6. Amazon Simple Notification Service (SNS): After the video is processed and the message is sent to the SQS queue, an SNS topic can be notified to send an in-app notification to the user that the processing is complete and the video is ready for use or distribution.

7. Practice Exams and Learning Resources: As mentioned in the instructor's introduction, practice exams with detailed explanations are crucial for preparing for the AWS Certified Solutions Architect Professional exam. These resources can help you understand the architecture and design patterns that best solve the problem at hand.

By using these AWS services, you can build a robust, scalable, and cost-effective video processing system that is capable of handling high volumes of video uploads and ensuring that all processes are reliable and fault-tolerant.