SAA-C03 Design Cost-Optimized Architectures Practice Test 5 — 15 Questions

Question 1

A media company keeps application logs in Amazon S3 for 400 days. The logs are read heavily for the first 30 days, occasionally for the next 90 days, and almost never after that. The team wants to lower storage cost without affecting retention requirements. Which two lifecycle transitions should it configure? Select two.

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

Accepted Answer

Transition the objects to S3 Standard-IA after 30 days.. After the first 30 days of heavy read access, transitioning to S3 Standard-IA reduces storage costs while still providing low-latency retrieval for the occasional reads that occur over the next 90 days. S3 Standard-IA is designed for data accessed infrequently but requires rapid access, matching the usage pattern described.

Answer

Transition the objects to S3 One Zone-IA after 30 days.

Answer

Keep the objects in S3 Standard for the full 400 days.

Answer

Use only S3 Intelligent-Tiering and never add archival transitions.

Question 2

A global software company distributes large installation packages from an Amazon S3 bucket. During release week, many users in the same region download the same file repeatedly, and the origin bill is rising because the same objects are fetched over and over. The team wants to lower origin data transfer and improve delivery cost. Which two actions should it take? Select two.

Accepted Answer

Put Amazon CloudFront in front of the S3 origin.. Amazon CloudFront acts as a content delivery network (CDN) that caches objects at edge locations close to users. By placing CloudFront in front of the S3 bucket, repeated downloads of the same file are served from the edge cache, drastically reducing the number of requests to the S3 origin and lowering data transfer costs from S3. CloudFront also offers free data transfer to the origin for cached content, further optimizing delivery cost.

Answer

Disable caching so every user always gets the newest file from S3.

Answer

Serve the downloads from a self-managed EC2 web server instead of S3.

Answer

Move the release packages to S3 Glacier Deep Archive for faster downloads.

Question 3

A marketing site serves versioned JavaScript and CSS files from an Amazon S3 origin through Amazon CloudFront. After a frontend release, the CloudFront cache hit ratio dropped because browsers now send an Authorization header on every static asset request even though the assets are public and do not require authentication. The team wants to lower origin load and improve cache efficiency. Which two actions should it take? Select two.

Accepted Answer

Create a separate CloudFront behavior for static assets with a cache policy and origin request policy that exclude the Authorization header.. Creating a separate CloudFront behavior for static assets allows you to attach a cache policy and an origin request policy that explicitly exclude the Authorization header. By not forwarding the Authorization header to the S3 origin, CloudFront can treat all requests for the same asset as cache hits, regardless of the header value, which restores the cache hit ratio and reduces origin load.

Answer

Forward the Authorization header to the origin for all static asset requests.

Answer

Set the cache TTL to zero so browsers always revalidate content.

Answer

Store the static assets in Amazon EFS so CloudFront can cache them more effectively.

Question 4

A development team stores application logs in Amazon CloudWatch Logs and has enabled detailed EC2 monitoring on every instance. Auditors require the logs to be retained for 90 days, but the operations team only needs the last 7 days to remain searchable in CloudWatch. Which two actions should they take to reduce monitoring cost? Select two.

Accepted Answer

Set the CloudWatch Logs retention period to 7 days and export or archive older logs in Amazon S3 or S3 Glacier for the remaining retention period.. CloudWatch Logs charges for data storage and search capabilities. By setting the retention period to 7 days, logs older than 7 days are automatically deleted from CloudWatch, eliminating ongoing storage and search costs. Exporting or archiving these logs to Amazon S3 or S3 Glacier satisfies the 90-day audit requirement at a much lower cost, as S3 and Glacier have minimal storage fees and no search costs.

Answer

Set the CloudWatch Logs retention period to 90 days so everything stays searchable in CloudWatch.

Answer

Send logs to DynamoDB because it is cheaper for long-term retention.

Answer

Enable detailed monitoring only during peak business hours on every instance.

Question 5

A company runs a customer portal on self-managed PostgreSQL on EC2, plus a self-managed RabbitMQ cluster for asynchronous work that only requires durable queueing and does not depend on RabbitMQ-specific exchange features. The operations team spends a lot of time patching, backing up, and scaling both systems. The business wants to reduce infrastructure management overhead and total cost of ownership. Which two changes are the best fit? Select two.

Accepted Answer

Migrate PostgreSQL to Amazon RDS for PostgreSQL.. Migrating PostgreSQL to Amazon RDS for PostgreSQL offloads patching, backups, and scaling to AWS, reducing operational overhead. RDS automates OS and database patching, provides automated backups with point-in-time recovery, and supports vertical scaling with minimal downtime. This directly addresses the team's time spent on maintenance while lowering TCO compared to self-managed EC2.

Answer

Move PostgreSQL to Amazon DynamoDB without redesigning the application.

Answer

Replace RabbitMQ with another EC2-based broker cluster for more control.

Answer

Keep the same design and increase instance sizes to simplify maintenance.

Question 6

A serverless checkout API has predictable traffic spikes every weekday at 09:00 UTC and low traffic the rest of the day. The team wants to reduce cost while keeping response times fast during the recurring spike. Which two actions should they take? Select two.

Accepted Answer

Use provisioned concurrency for the Lambda function during the expected spike window.. Provisioned concurrency initializes a specified number of Lambda execution environments in advance, ensuring no cold starts during traffic spikes. By scheduling provisioned concurrency to activate only during the 09:00 UTC window, the team keeps response times fast without paying for idle capacity the rest of the day.

Answer

Replace the API with a single always-on EC2 instance.

Answer

Keep provisioned concurrency permanently high all day and all week.

Answer

Disable API Gateway and use direct public internet access to Lambda.

Question 7

Based on the exhibit, your application runs entirely in private subnets and only needs to reach Amazon S3, Amazon DynamoDB, AWS Secrets Manager, and CloudWatch Logs. The monthly bill is dominated by NAT Gateway charges. Which change most directly reduces cost while preserving private connectivity to these AWS services?

Accepted Answer

Create S3 and DynamoDB gateway endpoints, create interface endpoints for Secrets Manager and CloudWatch Logs, update route tables, and remove the NAT Gateway.. It replaces the costly NAT Gateway with free VPC Gateway Endpoints for S3 and DynamoDB, and uses AWS PrivateLink interface endpoints for Secrets Manager and CloudWatch Logs. This eliminates all internet-bound data transfer costs while keeping traffic entirely within the AWS network, directly addressing the cost concern without sacrificing private connectivity.

Answer

Replace the NAT Gateway with an Internet Gateway and keep the current private subnet routes unchanged.

Answer

Add a second NAT Gateway in another Availability Zone to reduce cross-AZ data transfer charges.

Answer

Create only interface endpoints for all four services and keep the NAT Gateway for fallback.

Question 8

Based on the exhibit, the team wants to minimize compute cost for a workload with a steady 24/7 baseline and a separate nightly batch job that can be interrupted and resumed from checkpoints. They also expect to change EC2 instance families during the year as performance needs evolve. Which approach is the best fit?

Accepted Answer

Use a Compute Savings Plan to cover the steady baseline and run the nightly batch on Spot Instances.. A Compute Savings Plan covers any EC2 instance family (or even container/Fargate usage) at a discounted rate, making it ideal for the steady 24/7 baseline. The nightly batch job can be interrupted and resumed from checkpoints, which is a perfect use case for Spot Instances, offering up to 90% cost savings. This combination minimizes compute cost while maintaining flexibility to change instance families during the year.

Answer

Buy EC2 Instance Savings Plans for the baseline and run the nightly batch on On-Demand instances.

Answer

Purchase Standard Reserved Instances for all 12 instances and keep the current families fixed.

Answer

Run both tiers entirely on Spot Instances and rely on automatic restarts for the baseline web tier.

Question 9

Based on the exhibit, the team serves versioned JavaScript and CSS files from an S3 origin through CloudFront. After a release, the cache hit ratio dropped and origin fetches increased sharply. What change best reduces both CloudFront and S3 costs without changing the application’s public behavior?

Accepted Answer

Create a cache policy that excludes Authorization, cookies, and unnecessary query strings, and narrow the origin request policy to forward only the headers the S3 origin actually needs.. B is correct because versioned JavaScript and CSS files are immutable, so CloudFront should cache them aggressively. By creating a cache policy that excludes unnecessary headers (like Authorization and cookies) and query strings, and narrowing the origin request policy to forward only required headers, you maximize cache hits and reduce origin fetches. This directly lowers both CloudFront data transfer costs (fewer origin requests) and S3 request costs (fewer GET requests), without altering the application's public behavior.

Answer

Increase the CloudFront price class to include more edge locations.

Answer

Disable CloudFront and serve the files directly from S3 to avoid cache invalidation overhead.

Answer

Use Lambda@Edge to rewrite every request into a unique path so that clients never receive stale files.

Question 10

Based on the exhibit, the company wants to lower CloudWatch and EC2 monitoring costs. Auditors require logs to be retained for 90 days, but operations only uses detailed per-instance metrics during rare troubleshooting events. Which change best reduces recurring cost while preserving the required visibility?

Accepted Answer

Set CloudWatch Logs retention to 90 days for all log groups, and switch EC2 monitoring from detailed to basic except during incidents.. It directly addresses the two cost drivers: CloudWatch Logs storage costs are minimized by setting a 90-day retention policy (matching the audit requirement), and EC2 detailed monitoring (1-minute metrics) is replaced with basic monitoring (5-minute metrics) during normal operations, with the ability to switch back to detailed only when needed for troubleshooting. This preserves the required log retention and the ability to obtain high-resolution metrics on demand, while eliminating the recurring cost of storing logs indefinitely and paying for detailed monitoring on every instance.

Answer

Disable CloudWatch Logs entirely and rely on application local files for 90 days.

Answer

Increase the number of CloudWatch alarms so that metrics are collected less expensively.

Answer

Export all logs to Amazon S3 immediately and keep detailed monitoring enabled on every instance.

Question 11

Based on the exhibit, the company runs a self-managed RabbitMQ cluster on EC2 for asynchronous work. The queue only needs durable at-least-once delivery, and the application does not require AMQP-specific features such as exchanges, routing keys, or broker plugins. Which change is the best cost-optimization move?

Accepted Answer

Replace RabbitMQ with Amazon SQS Standard and keep the workers unchanged except for the queue client library.. Amazon SQS Standard provides at-least-once delivery and durable message storage without requiring AMQP-specific features like exchanges or routing keys. Replacing RabbitMQ with SQS eliminates the operational overhead of managing EC2 instances and RabbitMQ clusters, while SQS's pay-per-request pricing is more cost-effective than running EC2 instances 24/7 for a self-managed queue.

Answer

Replace RabbitMQ with Amazon MQ for RabbitMQ to keep the same protocol and reduce costs.

Answer

Increase the RabbitMQ instance size and add a fourth node for higher availability.

Answer

Move the queue to Amazon DynamoDB and use scans for consumers to detect new messages.

Question 12

A company runs Amazon EC2 instances in private subnets. Those instances only need to access Amazon S3 (read/write) and Amazon DynamoDB. The VPC currently routes all outbound traffic through a NAT Gateway, increasing monthly cost. What change most directly reduces NAT Gateway usage for these AWS services?

Accepted Answer

Remove the NAT Gateway path for S3 and DynamoDB by creating S3 Gateway VPC endpoints and DynamoDB Gateway VPC endpoints, and updating the private subnet route tables to route S3/DynamoDB traffic to those endpoints.. S3 Gateway VPC endpoints and DynamoDB Gateway VPC endpoints allow EC2 instances in private subnets to access these services directly over the AWS network without traversing a NAT Gateway. This eliminates NAT Gateway data processing charges for S3 and DynamoDB traffic, directly reducing costs. The route tables in the private subnets are updated to direct S3 and DynamoDB traffic to the gateway endpoints, bypassing the NAT Gateway entirely.

Answer

Keep the NAT Gateway but disable any cross-region routing settings for the route table entries that point to the NAT Gateway.

Answer

Create interface VPC endpoints for all services (including S3) and route S3 traffic to the interface endpoint network interfaces (ENIs).

Answer

Add an IAM policy that denies requests unless they originate from the public subnet, so the application sends fewer requests through the NAT Gateway.

Question 13

An S3 bucket stores application logs. After 30 days, the team rarely accesses the logs, but compliance requires keeping them for 18 months. Which setup most directly reduces storage cost while maintaining compliance?

Accepted Answer

Configure an S3 Lifecycle policy to transition objects to a colder storage class after 30 days and expire (delete) them after 18 months.. S3 Lifecycle policies allow you to automatically transition objects to cheaper storage classes (e.g., S3 Standard-IA or S3 Glacier Deep Archive) after 30 days, reducing storage costs for rarely accessed logs. The policy also sets an expiration action to delete objects after 18 months, meeting the compliance requirement without manual intervention.

Answer

Enable S3 Versioning and rely on deleting old versions after 30 days to reduce storage costs while keeping the latest data.

Answer

Move the bucket to a different AWS region farther from the users to reduce the likelihood of accidental reads and thereby lower storage costs.

Answer

Switch all objects to S3 Glacier Instant Retrieval immediately, regardless of object age, to minimize storage charges.

Question 14

A startup expects steady compute usage around the clock for the next year. They want to reduce costs compared to On-Demand pricing, without tightly planning specific instance types. Which option best matches their goal?

Accepted Answer

Purchase a Compute Savings Plan to receive discounted rates for a usage amount over a 1-year term.. A Compute Savings Plan offers the lowest prices on EC2 compute usage (including Fargate and Lambda) in exchange for a commitment to a consistent amount of compute (measured in $/hour) over a 1-year or 3-year term. This matches the startup's steady, predictable usage and provides up to 66% savings over On-Demand, while allowing flexibility to change instance families, sizes, regions, or even switch to containers without renegotiating the plan.

Answer

Purchase a Reserved Instance that must be tied to exactly one specific instance size (no flexibility to switch instance families).

Answer

Only use Spot Instances and set the workload to stop immediately if capacity is interrupted.

Answer

Rely on On-Demand pricing and add more alarms to detect when costs spike.

Question 15

An application runs on an EC2 Auto Scaling group. Over the last month, CPU utilization averaged 8% with no sustained memory pressure, and response times are stable. The team wants to lower monthly cost without changing the application. What is the most appropriate next step for cost optimization?

Accepted Answer

Evaluate a smaller EC2 instance type (via the Auto Scaling launch template/configuration) for the group and validate performance metrics after the change.. The application is over-provisioned: CPU utilization averages only 8% with no memory pressure and stable response times. By selecting a smaller EC2 instance type in the Auto Scaling launch template or configuration, you directly reduce the per-instance cost while maintaining adequate performance. This is the most straightforward cost optimization step without modifying the application code or architecture.

Answer

Increase desired capacity to 2x so utilization increases and instances become “more efficient.”

Answer

Disable Auto Scaling so the group never scales down to preserve baseline performance.

Answer

Switch the workload to Spot instances immediately to avoid On-Demand charges, regardless of interruption risk.