Amazon ElastiCache

[theodosiostziomakas]

A company has a fleet of running Spot EC2 instances behind an Application Load Balancer. The incoming traffic comes from various users across multiple AWS regions, and you would like to have the user’s session shared among the fleet of instances.

A Solutions Architect is required to set up a distributed session management layer that will provide scalable and shared data storage for the user sessions that supports multithreaded performance. The cache layer must also detect any node failures and replace the failed ones automatically.

Which of the following would be the best choice to meet the requirement while still providing sub-millisecond latency for the users?

A) AWS ELB sticky sessions

B) Amazon ElastiCache for Redis Global Datastore

C) Amazon RDS database with RDS Proxy

D) Amazon ElastiCache for Memcached with Auto Discovery

Hello everyone,

The correct answer in this question is D, and don’t get that. I answered B, as I thought that ElasticCache for Redis provides availability and scalability.

Thanks,
Theodosios

[Irene-TutorialsDojo]

Hi theodosiostziomakas,

Thanks for posting.

Amazon ElastiCache for Memcached with Auto Discovery is the correct answer. This service provides a distributed in-memory cache that supports multithreaded performance and sub-millisecond latency. Its auto-discovery feature efficiently detects node failures and automatically adjusts the cluster topology, making it ideal for scalable session management.

While ElastiCache for Redis offers high availability, its single-threaded architecture may not meet the high throughput requirements in this scenario.

If you have any further questions, feel free to ask!

Best,

Irene @ Tutorials Dojo

[riya das]

The correct answer is <strong data-start=”22″ data-end=”27″>B

[Irene-TutorialsDojo]

Hi Riya,

Thanks for your input!

To clarify, while ElastiCache for Redis Global Datastore offers high availability and cross-region replication, it is single-threaded per shard, which can limit throughput for highly concurrent session workloads.

In this case, the requirement calls for multithreaded performance, sub-millisecond latency, and automatic node recovery, which ElastiCache for Memcached with Auto Discovery is designed to handle better.

Hope this helps! Let me know if you have any more questions. 😊

Best,

Irene @ Tutorials Dojo

[riya das]

Thanks for your clarification