Here are the top 10 AWS Elastic Cache interview questions and their answers:

1. Q: What is AWS Elastic Cache?
   A: AWS Elastic Cache is a fully managed, in-memory data store service that helps improve the performance of web applications by retrieving data from fast, in-memory caches instead of relying on slower disk-based databases.

2. Q: What are the benefits of using AWS Elastic Cache?
   A: Some benefits of using AWS Elastic Cache include:

   • Improved application performance by reducing the load on backend databases.

   • Easy integration with existing applications through standard caching protocols.

   • Automatic scaling and high availability.

   • Support for popular caching engines like Redis and Memcached.

3. Q: Which caching engines are supported by AWS Elastic Cache?
   A: AWS Elastic Cache supports two popular caching engines: Redis and Memcached. Redis is a versatile, feature-rich caching engine, while Memcached is a simple and lightweight option.

4. Q: How does AWS Elastic Cache improve application performance?
   A: AWS Elastic Cache improves application performance by reducing the latency involved in fetching data from disk-based databases. By caching frequently accessed data in-memory, applications can retrieve data much faster, resulting in improved response times.

5. Q: What is the difference between Redis and Memcached in AWS Elastic Cache?
   A: Redis is a feature-rich caching engine that provides advanced data structures and additional functionality like persistence, replication, and pub/sub messaging. Memcached, on the other hand, is a simple and lightweight caching engine that offers basic key-value caching without any built-in persistence or advanced features.

6. Q: How does AWS Elastic Cache handle scaling and high availability?
   A: AWS Elastic Cache provides automatic scaling and high availability. It allows you to create cache clusters with multiple cache nodes, and it automatically scales the number of cache nodes based on the workload. Additionally, it replicates data across multiple nodes to ensure high availability and fault tolerance.

7. Q: Can I use AWS Elastic Cache with other AWS services?
   A: Yes, AWS Elastic Cache can be seamlessly integrated with other AWS services. For example, you can use Elastic Cache as a caching layer for your Amazon RDS databases or as a session store for your Amazon ElastiCache-enabled applications.

8. Q: How does AWS Elastic Cache handle data persistence?
   A: Redis, one of the caching engines supported by AWS Elastic Cache, provides options for data persistence. You can configure Redis to periodically save snapshots of the in-memory data to disk or enable replication to ensure data durability.

9. Q: What security measures does AWS Elastic Cache offer?
   A: AWS Elastic Cache provides several security features, including:

   • Encryption at rest using AWS Key Management Service (KMS).

   • In-transit encryption using SSL/TLS.

   • Integration with AWS Identity and Access Management (IAM) for access control.

   • VPC (Virtual Private Cloud) support to isolate the cache instances in your own private network.

10. Q: How can I monitor and optimize the performance of AWS Elastic Cache?
    A: AWS Elastic Cache provides several monitoring and optimization tools, such as: - CloudWatch metrics for monitoring cache utilization, CPU, memory, and network. - Enhanced monitoring for detailed cache-level metrics. - Integration with AWS X-Ray for distributed tracing and performance analysis. - Automatic backups and restoration to recover from failures.