SAA-C03 Design Cost-Optimized Architectures Practice Test 8 — 15 Questions

Question 1

An online retailer runs a steady-state order-processing application on Amazon EC2 that must run continuously for the next three years with predictable CPU usage. The finance team wants to reduce compute cost as much as possible and is willing to make a long-term commitment. The workload cannot tolerate interruption. Which purchasing approach provides the LARGEST discount while meeting these requirements?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Purchase a 3-year Compute Savings Plan with the All Upfront payment option.. For predictable, interruption-intolerant compute over a long horizon, a 3-year Compute Savings Plan with All Upfront payment yields the greatest discount. A Compute Savings Plan is more flexible than an EC2 Instance Savings Plan because it applies to any instance family and Region and to Fargate and Lambda usage, while the All Upfront option maximizes the rate reduction. Spot and On-Demand cannot meet the discount and reliability goals simultaneously.

Answer

Rely on Spot Instances with capacity-optimized allocation for the entire fleet.

Answer

Purchase a 3-year EC2 Instance Savings Plan with the No Upfront payment option.

Answer

Use On-Demand Instances and apply a Cost Allocation Tag to track spending.

Question 2

A solutions architect is reviewing a data lake built on Amazon S3 that receives 5 TB of new objects daily. Roughly 80% of the data is never read after the first month, but a small subset is accessed frequently for analytics dashboards. The team wants to reduce storage costs without changing application code and without manual intervention. (Choose two.)

Accepted Answer

Create an S3 Lifecycle rule to transition objects older than 30 days to S3 Standard-IA or S3 Glacier Instant Retrieval, depending on retrieval needs.. The data lake has a mixed access pattern: most objects go cold after a month while a small subset stays hot. Lifecycle transition rules move the cold majority to cheaper classes automatically, and S3 Intelligent-Tiering achieves the same outcome by monitoring access and shifting objects between tiers without retrieval fees. Both require no application changes and no manual effort, satisfying the stated constraints.

Answer

Enable S3 Transfer Acceleration on the bucket to speed uploads of the daily data.

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Convert the bucket to S3 Glacier Deep Archive for all objects immediately upon upload.

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Enable S3 Versioning and add a lifecycle rule to expire noncurrent versions after 7 days.

Question 3

You store application logs in an S3 bucket. After 30 days, the logs are rarely accessed, but you must retain them for 1 year for compliance. Which S3 feature is the best way to reduce storage cost while meeting the retention requirement?

Accepted Answer

Create an S3 lifecycle rule to transition older objects to a colder storage class after 30 days, then expire after 1 year. An S3 Lifecycle rule can automatically transition objects from S3 Standard to a colder storage class (e.g., S3 Glacier Instant Retrieval or S3 Glacier Deep Archive) after 30 days, reducing storage costs for rarely accessed logs. After 1 year, the rule can expire the objects, which permanently deletes them, meeting the compliance retention requirement without manual intervention.

Answer

Keep all logs in S3 Standard and rely on lower request rates to reduce cost

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Copy logs to EBS snapshots each week and delete the original files

Answer

Use S3 replication to a second bucket in another region to reduce costs

Question 4

CloudWatch metrics show your EC2 instances have average CPU utilization around 10% with stable performance over several weeks. The application does not require additional headroom right now. What is the most effective cost-optimization action?

Accepted Answer

Right-size the instances to a smaller size that matches the observed utilization. Right-sizing EC2 instances to match observed utilization is the most effective cost-optimization action because the current instances are over-provisioned (average CPU at 10%). By selecting a smaller instance type that aligns with the actual workload, you reduce hourly costs without impacting performance, as the application has stable behavior and no need for headroom.

Answer

Increase the Auto Scaling desired capacity to add more instances

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Switch to Spot Instances immediately even though interruptions would impact users

Answer

Disable detailed monitoring to reduce CPU usage from the monitoring agent

Question 5

A marketing site serves versioned JavaScript and CSS files from Amazon S3 through CloudFront. The origin bill is rising because CloudFront keeps fetching the same files too often, and the application never changes a file at the same URL once it is published. Which two changes should you make? Select two.

Accepted Answer

Set long-lived Cache-Control headers, such as a high max-age and immutable policy, on the versioned assets.. Setting long-lived Cache-Control headers (e.g., `max-age=31536000` and `immutable`) on versioned assets tells CloudFront and browsers to cache the files aggressively. Since the application never changes a file at the same URL, this eliminates redundant origin fetches, directly reducing the origin bill.

Answer

Move the static assets to an EC2 web server behind an Application Load Balancer.

Answer

Disable CloudFront caching so every request always reaches the origin.

Answer

Add more viewer-facing headers to the cache key so each browser variation gets a unique cached object.

Question 6

An application serves static images through Amazon CloudFront. The team observes higher-than-expected origin fetches, which increases origin bandwidth costs. Which change most directly improves CloudFront cache reuse to reduce origin requests for the static content?

Accepted Answer

Set appropriate Cache-Control headers (or origin cache settings) so CloudFront caches responses longer. Setting appropriate Cache-Control headers (e.g., max-age or s-maxage) or configuring origin cache settings tells CloudFront how long to keep objects in its edge cache before revalidating with the origin. By extending the cache duration, CloudFront serves more requests from its cache, reducing the number of origin fetches and lowering bandwidth costs.

Answer

Disable caching for the distribution so every request goes back to the origin

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Configure CloudFront to forward all request headers and query strings to the origin

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Move the S3 bucket to a different AWS Region, without changing CloudFront caching behavior

Question 7

Your team runs a batch processing workload on EC2 that can tolerate interruptions. If an instance is terminated, the job can restart from checkpoints. To reduce compute costs, what is the most cost-optimized approach?

Accepted Answer

Use EC2 Spot Instances for the batch workers. Spot Instances are ideal for fault-tolerant, interruption-tolerant batch workloads because they offer significant cost savings (up to 90% compared to On-Demand) while allowing the job to resume from checkpoints if terminated. This aligns perfectly with the requirement to reduce compute costs without compromising the ability to restart interrupted jobs.

Answer

Use Dedicated Hosts to ensure capacity for the cheapest instance

Answer

Use On-Demand instances and schedule extra runs to offset interruptions

Answer

Use Reserved Instances only, because they eliminate instance termination events

Question 8

A company has a steady, predictable workload that must run continuously (24/7) in a single AWS Region. The team wants the lowest cost option available for this steady usage, but also expects they may choose different EC2 instance families in the future (without re-buying compute discounts). Which AWS purchase option best meets these goals?

Accepted Answer

Compute Savings Plans, committed for a 1- to 3-year term in the Region. Compute Savings Plans offer the lowest cost for steady, predictable workloads while providing instance family flexibility within a Region. Unlike Reserved Instances, they automatically apply discounts to any EC2 instance family (and even Fargate/Lambda) in the chosen Region, so the company can switch instance families in the future without losing the discount. A 1- or 3-year commitment yields significant savings (up to 66%) compared to On-Demand, making it the optimal choice for this scenario.

Answer

On-Demand Instances only, because they automatically adjust to future needs

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Standard Reserved Instances tied to a single instance type and Availability Zone

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EC2 Spot Instances, because they are always cheaper than savings programs

Question 9

A web service runs continuously on AWS 24/7. The team expects steady compute usage for the next 12–24 months, but may change instance families/sizes as performance tuning continues. Which purchase option best reduces cost while keeping flexibility to change instance types?

Accepted Answer

Use Compute Savings Plans for the expected steady usage. Compute Savings Plans offer the lowest prices (up to 66% off On-Demand) in exchange for a commitment to a consistent amount of compute usage (measured in $/hour) for a 1- or 3-year term. Unlike Reserved Instances, they automatically apply to any EC2 instance family, size, OS, or region, giving you the flexibility to change instance types as performance tuning evolves, while still reducing costs for steady-state workloads.

Answer

Buy EC2 On-Demand instances and rely on future Spot capacity for discounts

Answer

Buy Reserved Instances with a fixed instance type and region

Answer

Buy Spot Instances and stop scaling to avoid interruption risk

Question 10

A team stores application logs in Amazon S3. They need access to the logs only occasionally for troubleshooting (infrequent access), and they want to reduce storage cost automatically over time without manually moving objects. What should they implement?

Accepted Answer

An S3 lifecycle policy that transitions objects to a lower-cost storage class after a set number of days. An S3 lifecycle policy can automatically transition objects from S3 Standard to lower-cost storage classes (e.g., S3 Standard-IA, S3 One Zone-IA, or S3 Glacier Instant Retrieval) after a specified number of days. This meets the requirement of reducing storage costs over time for infrequently accessed logs without manual intervention, as the policy automates the movement based on object age.

Answer

An S3 lifecycle policy that deletes objects after 1 day to eliminate storage costs

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An S3 lifecycle policy that keeps all objects in S3 Standard and only applies compression at read time

Answer

A policy that changes bucket encryption from SSE-S3 to SSE-KMS to reduce storage cost

Question 11

Your global users access static images stored in S3. Origin bandwidth costs are higher than expected because CloudFront is not caching effectively. What change most directly reduces origin fetches (and typically lowers data transfer costs) without changing application logic?

Accepted Answer

Configure CloudFront caching by setting appropriate cache-control headers and/or CloudFront cache policy/TTL values for the static objects. The high origin bandwidth costs are caused by CloudFront not caching effectively, meaning too many requests reach the S3 origin. By configuring appropriate Cache-Control headers or a CloudFront cache policy with optimal TTL values, you ensure that CloudFront caches the static images at edge locations for longer periods. This directly reduces the number of origin fetches, lowering data transfer costs without any changes to the application logic.

Answer

Disable CloudFront caching so every request goes back to S3 for the latest image

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Route users directly to the S3 website endpoint to bypass CloudFront

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Turn on a NAT Gateway for the CloudFront origin to reduce bandwidth charges

Question 12

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

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Reserved Instances with no interruption handling

Question 13

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

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

Question 14

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 AWS Organizations consolidated billing places all four accounts under a single payer account, which aggregates usage for volume discounts (such as S3 tiered pricing and Reserved Instance/Savings Plans sharing), centralizes purchasing, and provides a single bill for spend visibility — exactly matching the CTO's goals of lower cost, less overhead, and central purchasing. Option C is correct because replacing self-managed EC2-based databases and file servers with managed services like Amazon RDS and Amazon S3 reduces operational overhead (patching, backups, scaling handled by AWS) and typically lowers total cost, aligning with the startup's desire to minimize operational burden. Option B is wrong because separate payer accounts fragment billing, forfeit volume discounts and RI/SP sharing, and increase overhead rather than reduce it. Option D is wrong because Dedicated Hosts are a premium-priced option intended for licensing/compliance needs, not a cost-saving measure for sandbox workloads. Option E is wrong because AWS Budgets is a free cost-visibility and alerting tool; disabling it removes the very spend visibility the CTO wants, and consolidated billing alone does not provide budget alerts or thresholds.

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 15

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 enforcing and activating cost allocation tags (e.g., project tags) is the prerequisite for attributing AWS charges to projects in billing data, enabling accurate chargeback. Option B is correct because AWS Budgets supports cost budgets scoped by tag, account, or service, and can trigger SNS alerts and budget actions (such as applying SCPs or stopping instances) before overspend occurs. Option C is correct because Cost Explorer and Cost and Usage Reports (CUR) provide the consolidated, multi-account analysis by account, tag, and service that Finance needs without manually opening each account, especially when integrated with AWS Organizations. Option D is not appropriate because merely isolating teams into separate accounts without tagging does not provide project-level chargeback or the required tag-based views. Option E is incorrect because CloudTrail records API activity for auditing, not resource costs, and cannot estimate spend by resource.

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.