A distributed system needs extremely low network latency between a set of EC2 instances running the same workload. The team wants the instances to be placed as close together as AWS allows to reduce round-trip time. Which placement strategy should the architect use?

Use a Spread placement group across multiple Availability Zones to maximize fault tolerance.

Spread placement groups maximize resilience by dispersing instances across hardware failure domains, including multiple AZs. While useful for availability, it typically does not optimize for the lowest possible network latency between nodes. The scenario explicitly requires closeness to reduce round-trip time, which is the Cluster placement group strength.

Use the default placement strategy without specifying a placement group.

Default placement does not guarantee low-latency proximity between instances. Even though some instances may end up relatively close, it provides no assurance for tight inter-node communication requirements. The system’s need for extremely low latency requires an explicit placement strategy, not reliance on chance.

Use a placement group of type Partition to ensure independent failure of each instance.

Partition placement groups are aimed at isolating instances into separate logical partitions, often for large clusters. This improves the ability to isolate failures but does not specifically prioritize minimal latency between all instances in one communication set. The scenario’s primary objective is lower round-trip time, which points to Cluster placement.

What does this SAA-C03 question test?

Read the scenario before looking for a memorised answer.

What is the correct answer to this question?

The correct answer is: Use a Cluster placement group for the instances that must communicate frequently over low latency. — For extremely low network latency between a set of EC2 instances, Cluster placement groups are designed to place instances in close proximity within a single Availability Zone. This reduces network distance and typically improves round-trip time for tightly coupled, frequently communicating workloads. Spread placement groups prioritize fault isolation, not inter-instance performance, and the default strategy provides no latency guarantees. Partition placement groups focus on isolating capacity across partitions and is not the primary tool for minimizing latency across all nodes. Spread (B) disperses instances for availability, so latency between nodes generally won’t be minimized. Default placement (C) provides no control or guarantees on proximity, so latency requirements may not be met. Partition (D) emphasizes isolation across partitions rather than optimizing communication distance for the entire set. Cluster placement best matches the requirement to be as close together as AWS allows for inter-node round-trip time.

What should I do if I get this SAA-C03 question wrong?

Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.