AWS Certified Solutions Architect – Professional — Question 668

A company is deploying a distributed in-memory database on a fleet of Amazon EC2 instances. The fleet consists of a primary node and eight worker nodes. The primary node is responsible for monitoring cluster health, accepting user requests, distributing user requests to worker nodes, and sending an aggregate response back to a client. Worker nodes communicate with each other to replicate data partitions.
The company requires the lowest possible networking latency to achieve maximum performance.
Which solution will meet these requirements?

Answer options

• A. Launch memory optimized EC2 instances in a partition placement group.
• B. Launch compute optimized EC2 instances in a partition placement group.
• C. Launch memory optimized EC2 instances in a cluster placement group
• D. Launch compute optimized EC2 instances in a spread placement group.

Correct answer: C

Explanation

An in-memory database requires high memory capacity, making memory optimized EC2 instances the ideal choice. To achieve the lowest possible network latency and high-throughput communication between the nodes, a cluster placement group is required as it logically groups instances close together within a single Availability Zone. Partition and spread placement groups are designed to minimize the risk of simultaneous hardware failures but do not offer the ultra-low latency benefits of a cluster placement group.