ANS-C01 Network Design Practice Question

Correct answer & explanation

Option C is correct. A placement group with a partition strategy spreads instances across logical partitions but within a single AZ, which does not provide multi-AZ HA. For low latency across AZs, a cluster placement group is not possible because it is limited to a single AZ. Therefore, the best practice is to place instances in the same VPC and subnet in the same AZ for lowest latency, but that sacrifices AZ-level HA. Actually, the question asks for low latency across multiple AZs, so the best option is to use a cluster placement group in a single AZ (which is not across AZs). The correct answer is to use a cluster placement group in a single AZ, but the option that mentions that is D? Let me review: Option D says 'Cluster placement group across two AZs' which is not possible. Option C says 'Partition placement group across two AZs' which provides low latency? Actually, partition placement groups are not designed for low latency; they are for large distributed workloads. The correct answer is that cluster placement groups are limited to one AZ, so for low latency across AZs, you cannot use placement groups. The question might be tricky. The best answer is B: 'Use a spread placement group across two AZs' but spread placement groups increase latency. I think the intended answer is D: 'Cluster placement group across two AZs' is not possible, so that's wrong. Option A: 'No placement group, use Enhanced Networking' is the correct approach because placement groups cannot be used across AZs for low latency. Actually, Enhanced Networking (ENA) provides low latency regardless. So correct answer is A.

Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.