Answer: Use an Amazon DynamoDB table to store customer session information., Deploy an Amazon ElastiCache for Redis cluster to store customer session information.

## Explanation **Correct Answers: B and D** **B. Use an Amazon DynamoDB table to store customer session information.** - DynamoDB is a fully managed NoSQL database service that provides durable storage with high availability and scalability. - It can store session data durably with automatic replication across multiple Availability Zones. - DynamoDB offers single-digit millisecond latency, making it suitable for session management. - Data is persisted to disk, ensuring durability even if instances fail. **D. Deploy an Amazon ElastiCache for Redis cluster to store customer session information.** - ElastiCache for Redis provides in-memory data storage with optional persistence features. - Redis can be configured with AOF (Append Only File) or RDB snapshots for durability. - It offers extremely low latency for session data access. - Redis clustering provides high availability and scalability. **Why other options are incorrect:** **A. Turn on the sticky sessions feature (session affinity) on the ALB.** - Sticky sessions route user requests to the same EC2 instance, but session data is still stored locally on that instance. - If the instance fails or is terminated by Auto Scaling, session data is lost. - This does not provide durable storage of session data. **C. Deploy an Amazon Cognito user pool to manage user session information.** - Amazon Cognito is primarily for user authentication and authorization, not for storing general session data during ecommerce transactions. - While it manages authentication sessions, it's not designed for storing shopping cart data or transaction state. **E. Use AWS Systems Manager Application Manager in the application to manage user session information.** - AWS Systems Manager Application Manager is for operational management, monitoring, and troubleshooting of applications. - It's not designed for storing customer session data. **Key Requirements Met:** 1. **Durable storage** - Both DynamoDB and ElastiCache Redis (with persistence enabled) provide durable storage. 2. **Optimized session management** - Both provide low-latency access suitable for ecommerce transactions. 3. **Scalability** - Both services can scale to handle varying loads. 4. **High availability** - Both offer multi-AZ deployments for fault tolerance.

Author: LeetQuiz Editorial Team