SAA-C03 Design Cost-Optimized Architectures Practice Test 2 — 15 Questions

Question 1

You need to run batch jobs on EC2. The jobs can tolerate interruptions: if an instance is terminated, the job can restart from checkpoints. To reduce compute cost as much as possible, what is the best choice?

Accepted Answer

EC2 Spot Instances with checkpoint-based interruption handling. Spot Instances offer significant cost savings (up to 90% compared to On-Demand) but can be reclaimed by AWS with a two-minute warning. Since the batch jobs can tolerate interruptions and restart from checkpoints, Spot Instances are the most cost-effective choice. This aligns with the requirement to reduce compute cost as much as possible while handling interruptions gracefully.

Answer

EC2 On-Demand Instances to avoid interruptions

Answer

Savings Plans to guarantee capacity for the entire year

Answer

Reserved Instances with no interruption handling

Question 2

A containerized service runs in private subnets and retrieves secrets from AWS Secrets Manager and configuration parameters from AWS Systems Manager Parameter Store on startup. A NAT Gateway is currently used only for these AWS API calls, and the security team wants to eliminate that recurring charge. Which two endpoints should be added? Select two.

Accepted Answer

Create an interface VPC endpoint for AWS Secrets Manager.. Option A is correct because AWS Secrets Manager is accessed via API calls over HTTPS, and an interface VPC endpoint (powered by AWS PrivateLink) allows private connectivity to the service without traversing the internet or a NAT Gateway. This eliminates the need for the NAT Gateway for Secrets Manager traffic, reducing costs and improving security by keeping traffic within the AWS network.

Answer

Create a gateway VPC endpoint for Amazon S3 instead.

Answer

Add an Internet Gateway and send the traffic through public subnets.

Answer

Replace the NAT Gateway with a NAT instance.

Question 3

A line-of-business application runs on EC2 instances 24/7 with predictable usage for the next year. The application will stay in the same Region, and the team does not want to manage capacity interruptions. Which two purchase options can reduce cost compared with pure On-Demand pricing? Select two.

Accepted Answer

Buy Compute Savings Plans for the expected steady usage.. Compute Savings Plans (A) offer a flexible discount (up to 66%) in exchange for a 1- or 3-year commitment to a consistent amount of compute usage (measured in $/hour), automatically applying to any EC2 instance family, region, or even AWS Fargate/Lambda. This reduces cost compared to On-Demand while avoiding capacity interruptions, as the commitment covers the predictable steady-state usage. Standard Reserved Instances (B) provide a similar discount (up to 72%) for a specific instance family in a specific region, also with a 1- or 3-year term, and guarantee capacity for the specified AZ if you choose a zonal reservation, ensuring no interruptions.

Answer

Move the fleet to Spot Instances.

Answer

Use Dedicated Hosts to reserve physical servers for the application.

Answer

Stay entirely on On-Demand Instances because they are already the cheapest option.

Question 4

A compliance archive writes one log file per day to Amazon S3. The logs are almost never accessed after day 30, but if they are needed they must still be retrievable in milliseconds. They must be deleted automatically after one year. Which two lifecycle settings should you apply? Select two.

Accepted Answer

Transition the objects to S3 Glacier Instant Retrieval after 30 days.. Option A is correct because S3 Glacier Instant Retrieval provides millisecond retrieval times for archived data, meeting the requirement that logs must be retrievable in milliseconds after 30 days. This storage class is designed for long-lived, rarely accessed data that still needs immediate access, making it ideal for compliance archives that are almost never accessed but must be available instantly when needed.

Answer

Transition the objects to S3 Standard-IA after 30 days.

Answer

Keep the logs in S3 Standard indefinitely and delete them manually when needed.

Answer

Replicate the logs to another Region for cheaper archival storage.

Question 5

A workload runs in private subnets. It must access AWS services such as Amazon S3, but the company wants to avoid using a NAT Gateway to reduce outbound networking costs. What is the best solution?

Accepted Answer

Create VPC endpoints for the required AWS services and route traffic to them. VPC endpoints (Gateway Endpoints for S3 and DynamoDB, or Interface Endpoints for other services) allow instances in private subnets to access AWS services privately without traversing the internet or a NAT Gateway. This eliminates NAT Gateway data processing and hourly charges, directly reducing outbound networking costs while keeping traffic within the AWS network.

Answer

Attach Elastic IP addresses to instances in private subnets

Answer

Install a NAT Gateway in every subnet to minimize routing hops

Answer

Open outbound internet access with a security group rule to reach service endpoints directly

Question 6

An application stores user-uploaded binaries in S3. Access is unpredictable for the first month, then most objects become cold. The team wants the cheapest approach that avoids manually guessing access patterns. Which two actions are best? Select two.

Accepted Answer

Enable S3 Intelligent-Tiering on the bucket.. Option A is correct because S3 Intelligent-Tiering automatically moves objects between access tiers (frequent, infrequent, archive instant, and deep archive) based on changing access patterns, without manual lifecycle rules. This is ideal for unpredictable access in the first month followed by cold storage, as it optimizes cost by charging only for the storage tier actually used per object, with a small monthly monitoring fee per object.

Answer

Keep all objects in S3 Standard because lifecycle transitions add too much management.

Answer

Copy all binaries to Amazon EFS so retrieval is faster.

Answer

Disable versioning because S3 Intelligent-Tiering needs it to work.

Question 7

A photo studio stores original project archives in Amazon S3. Objects are read heavily for 14 days after upload, occasionally during the next 11 months, and almost never after one year. The team wants the lowest storage cost while keeping retrieval within minutes during the first year. Which three actions are best? Select three.

Accepted Answer

Keep new objects in S3 Standard for the first 14 days.. A is correct because S3 Standard is designed for frequently accessed data with low latency and high throughput, making it ideal for the first 14 days when objects are read heavily. After this period, transitioning to S3 Standard-IA reduces storage costs while still providing millisecond retrieval for occasional access during the next 11 months.

Answer

Transition objects to S3 Glacier Flexible Retrieval after 14 days.

Answer

Disable versioning to make the lifecycle rules work correctly.

Question 8

A media company runs a 24/7 ingestion API on EC2 behind an Application Load Balancer and a nightly transcoding job that can resume from checkpoints. The API fleet runs at roughly 65 percent CPU all day, while the batch workers sit idle most of the time. The company wants to cut compute cost without risking the API. Which two changes should they make? Select two.

Accepted Answer

Purchase a Compute Savings Plan for the always-on API fleet.. A is correct because a Compute Savings Plan offers the largest discount (up to 66%) in exchange for a 1- or 3-year commitment to a consistent amount of compute usage (measured in $/hour), regardless of instance family, region, or OS. The API fleet runs at a steady 65% CPU 24/7, making it an ideal candidate for this flexible, cost-saving commitment without locking into a specific instance type.

Answer

Replace the API fleet with Dedicated Hosts to lock in lower rates.

Answer

Buy Standard Reserved Instances for the batch workers and keep them running 24/7.

Answer

Increase the worker Auto Scaling minimum to prevent Spot interruptions.

Question 9

A company processes product-image uploads in bursts. Each transform takes up to ten minutes, and every job can be retried safely from the beginning. The current EC2 worker fleet is idle most of the day. Which two changes most reduce cost and idle capacity? Select two.

Accepted Answer

Buffer jobs in Amazon SQS and let workers scale from queue depth.. Option A is correct because Amazon SQS decouples the bursty upload workload from the worker fleet. By using SQS queue depth as the metric for an Auto Scaling policy, workers scale up only when jobs are waiting and scale down to zero during idle periods, eliminating wasted capacity. This directly reduces cost by matching compute resources to actual demand.

Answer

Keep a fixed fleet of m6i.large instances in an Auto Scaling group with a higher minimum.

Answer

Use Reserved Instances for the workers even though demand is highly bursty.

Answer

Process uploads only during a nightly window so the fleet looks busier.

Question 10

A product catalog system uses a relational database for orders and a simple key-value profile store for shopping carts. Traffic is unpredictable, and the company wants to avoid paying for large idle database instances. Which two choices are best? Select two.

Accepted Answer

Use Aurora Serverless v2 for the relational order system.. Aurora Serverless v2 automatically scales compute and memory capacity based on application demand, making it ideal for unpredictable traffic. It eliminates the need to provision for peak load, reducing costs by scaling to zero when idle. This matches the requirement to avoid paying for large idle database instances.

Answer

Keep both workloads on large provisioned RDS instances and add read replicas for the cart store.

Answer

Use DynamoDB provisioned capacity with a fixed minimum despite the unpredictable traffic.

Answer

Replace the relational order system with a wide-column table to reduce SQL licensing.

Question 11

A SaaS vendor has a steady 24/7 control plane on ECS and several small event-driven tasks that currently run on a separate always-on service. Management wants the billing discount that applies across both ECS and Lambda usage without committing to a specific instance family. Which two actions are best? Select two.

Accepted Answer

Buy a Compute Savings Plan for the predictable baseline usage.. A Compute Savings Plan offers the largest discount (up to 66%) across both ECS and Lambda usage without committing to a specific instance family, which matches the requirement to cover both services flexibly. It applies to any EC2 instance, including those used by ECS, and to AWS Lambda compute, making it ideal for a mixed workload with a predictable baseline.

Answer

Buy an EC2 Instance Savings Plan tied to one instance family for all workloads.

Answer

Use Spot Instances for the control plane because it is the largest bill.

Answer

Increase the ECS desired count so Lambda can be removed.

Question 12

A startup has three sandbox accounts and one production account. The CTO wants lower cost and operational overhead while keeping central purchasing and spend visibility. Which two actions are best? Select two.

Accepted Answer

Enable consolidated billing under AWS Organizations so discounts and shared purchasing apply across accounts.. Option A is correct because enabling consolidated billing under AWS Organizations aggregates usage across all accounts, allowing the startup to benefit from volume discounts, Reserved Instance sharing, and Savings Plans across the sandbox and production accounts. This reduces operational overhead by centralizing payment and provides a single view of spend, meeting the CTO's requirements for cost and visibility.

Answer

Move each sandbox to its own payer account to isolate spend from the rest.

Answer

Buy Dedicated Hosts for sandbox workloads to get a lower blended rate.

Answer

Disable AWS Budgets because consolidated billing already solves visibility.

Question 13

A retailer runs a reporting-heavy relational app on Amazon RDS MySQL. Peak dashboard traffic lasts only three hours each day, but the database is sized for the peak all day. The business wants lower cost without rewriting the application. Which three actions are best? Select three.

Accepted Answer

Right-size the writer based on actual utilization instead of peak guesses.. Option A is correct because right-sizing the RDS instance based on actual utilization metrics (e.g., CPU, memory, connections) directly reduces cost by eliminating over-provisioning for the 3-hour peak. This is a fundamental cost-optimization practice that avoids paying for idle capacity during the remaining 21 hours.

Answer

Migrate to DynamoDB immediately because every relational workload is more expensive.

Answer

Increase provisioned IOPS permanently so the monthly bill drops.

Question 14

Multiple teams share one AWS Organization. Finance wants chargeback by project, alerts before overspend, and monthly views by account without manually opening each account. Which three actions best fit? Select three.

Accepted Answer

Enforce cost allocation tags on resources and activate them for billing reports.. Option A is correct because cost allocation tags, when activated for billing reports, allow you to tag resources with project-specific metadata (e.g., 'Project:Alpha'). AWS then includes these tags in the Cost and Usage Reports (CUR) and Cost Explorer, enabling Finance to filter and allocate costs by project without manual account inspection. This directly supports chargeback by project and monthly views by account and tag.

Answer

Put every team in a separate AWS account and ignore tagging.

Answer

Use CloudTrail trails to estimate spend by resource because it records API calls.

Question 15

A fleet of test servers is rebuilt every week from AMIs. EBS volumes are often left behind after termination, and the team creates daily snapshots of every volume even when nothing changes. Which three actions most reduce storage cost while preserving recovery options? Select three.

Accepted Answer

Use gp3 for new EBS volumes instead of gp2 when similar performance is enough.. Option A is correct because gp3 volumes offer a baseline performance that is often sufficient for test servers, and they are typically more cost-effective than gp2 volumes for the same amount of storage. By using gp3, you avoid paying for the additional IOPS that gp2 includes by default, which can reduce costs when the workload does not require high performance. This directly addresses the goal of reducing storage costs while maintaining adequate performance for recovery purposes.

Answer

Keep unattached volumes around for troubleshooting after instance termination.

Answer

Raise provisioned IOPS on every volume so snapshot restore time feels faster.