SAA-C03 Design Cost-Optimized Architectures Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Cross-Region data replication for all data

  Why it's wrong here

  Cross-Region data replication for all data is an incorrect cost optimization because it adds significant AWS data transfer charges and additional storage costs in the destination region. While replication improves disaster recovery or access latency, a marketing site typically does not require replicating every dataset to another region, especially when simpler backup strategies (e.g., S3 versioning or cross-Region backup snapshots) provide resilience at a fraction of the cost. Replication should be driven by specific business continuity or availability requirements, not blanket cost cutting.

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  io2 Block Express volumes for all instances

  Why it's wrong here

  io2 Block Express volumes for all instances is an incorrect cost reduction choice because io2 Block Express is a premium, high-performance SSD engineered for mission-critical workloads that need sustained high IOPS, low latency, and high durability (99.999% availability). A marketing site's web servers, OS volumes, and application logs typically do not demand that performance level, so attaching these volumes to every instance would dramatically inflate storage costs. The right move is to use gp3 volumes for general purpose workloads and only upgrade selected volumes to io2 if performance testing proves an actual bottleneck, not by default.

• ✓

  AWS Graviton-based instances after performance testing

  Why this is correct

  AWS Graviton-based instances after performance testing is the correct approach because Graviton processors (arm64 architecture) often deliver up to 20% better price-performance than comparable x86 instances for scale-out, stateless, and lighter-workload deployments like a marketing site running open-source software. The key is to first run performance testing to verify that your specific application stack—including any compiled binaries, libraries, or dependencies—is fully compatible and performs adequately on the arm64 architecture. If the workload is portable (e.g., running on Linux with open-source code), moving to Graviton instances reduces compute cost without sacrificing performance, making it a cost-effective modernization step.

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  Dedicated Hosts by default

  Why it's wrong here

  Dedicated Hosts by default is an incorrect cost optimization because a Dedicated Host grants you a physical server exclusively for your use, which is significantly more expensive than shared tenancy instances on a per-hour basis. Dedicated Hosts are meant for specific licensing requirements (such as Windows Server with per-socket licenses) or strict compliance mandates that require server-bound licensing, not for general cost reduction. For a marketing site without those constraints, you would pay for the entire physical host even when idle, so using Savings Plans or Reserved Instances on shared hardware is far more cost-efficient.

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