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

Question 1

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.. Option B is correct because 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 2

Based on the exhibit, the company stores 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 very rarely after that. Retrieval after day 120 can take up to several hours, but the data must remain available until day 400. Which lifecycle policy is the most cost-effective fit?

Accepted Answer

Transition logs to S3 Standard-IA after 30 days, then to S3 Glacier Flexible Retrieval after 120 days, and expire them at 400 days.. Option B is correct because it aligns the storage class transitions with the access patterns: S3 Standard for the first 30 days (heavy reads), S3 Standard-IA for the next 90 days (occasional reads), and S3 Glacier Flexible Retrieval for the remaining period (rare access, with retrieval up to several hours acceptable). This minimizes storage costs while ensuring data availability until day 400, where lifecycle expiration removes the objects.

Answer

Keep all logs in S3 Standard for 400 days and enable requester pays to reduce the company's bill.

Answer

Transition logs directly from S3 Standard to S3 Glacier Deep Archive after 30 days and expire them at 400 days.

Answer

Move logs to S3 Intelligent-Tiering only and disable lifecycle transitions because access is unpredictable.

Question 3

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 4

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.. Option C is correct because 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 5

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.. Option A is correct because 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 6

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.. Option A is correct because 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 7

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.. Option A is correct because 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 8

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 9

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.. Option A is correct because 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.

Question 10

A team stores application logs in Amazon CloudWatch Logs. They enabled long retention and detailed dashboards, resulting in higher-than-expected monthly spend. Compliance requires retaining logs for 90 days, but operations only needs aggregated views. Which change most directly reduces CloudWatch Logs cost while meeting the requirement?

Accepted Answer

Set the CloudWatch Logs log group retention period to 90 days for the relevant log groups.. Setting the CloudWatch Logs log group retention period to 90 days directly reduces storage costs by automatically expiring logs after the compliance-required duration. This eliminates the cost of storing logs beyond 90 days, which was the primary driver of the higher-than-expected spend, while still retaining the data for the mandated period and allowing aggregated views via dashboards.

Answer

Disable VPC flow logs so the applications stop producing logs automatically.

Answer

Increase the logging level to DEBUG to reduce the number of log events by batching them.

Answer

Turn off CloudWatch alarms so logs stop being ingested into CloudWatch Logs.

Question 11

A website serves versioned JavaScript and CSS files through CloudFront, but origin fetches are still high and the CloudFront bill increased. Developers confirm that URLs include a version in the filename (for example, app.1.4.2.js). What CloudFront behavior/configuration is most likely to reduce origin fetches and associated costs?

Accepted Answer

Set long cache headers (for example, Cache-Control: max-age and immutable) on those versioned assets so CloudFront caches them longer.. Setting long cache headers like `Cache-Control: max-age=31536000, immutable` on versioned assets tells CloudFront to cache these objects at edge locations for an extended period. Since the filename changes with each new version, CloudFront treats each version as a unique object and will not re-fetch the old version from the origin, dramatically reducing origin fetches and associated costs.

Answer

Disable compression to reduce CPU time spent at the edge and therefore reduce total cost.

Answer

Lower the cache policy TTLs so clients always get the newest assets quickly.

Answer

Remove version identifiers from filenames so CloudFront caches fewer unique objects.

Question 12

A SaaS company runs a production API on an EC2 Auto Scaling group with steady demand 24/7. The team uses multiple instance types over time (they switch types during tuning) but the overall compute hours are stable. They want a cost reduction without committing to a specific instance type or size. Which AWS pricing option best meets the requirement?

Accepted Answer

Purchase a Compute Savings Plan for the region and commit to a dollar-per-hour amount. B is correct because a Compute Savings Plan provides the flexibility to change instance types, sizes, and even compute services (e.g., EC2, Fargate, Lambda) within a region while still receiving discounted rates (up to 66% vs. on-demand). This matches the requirement of reducing costs without committing to a specific instance type or size, as the plan is based on a dollar-per-hour commitment rather than instance family or tenancy.

Answer

Buy EC2 Spot Instances for the Auto Scaling group to maximize savings

Answer

Purchase Reserved Instances that are limited to a single specific instance type in the Auto Scaling group

Answer

Use on-demand only, and rely on Auto Scaling to reduce cost during low utilization

Question 13

A team stores application logs in an S3 bucket. They keep logs for 18 months for compliance. Access patterns: logs are heavily accessed during the first 30 days, rarely accessed between days 31 and 180, and almost never accessed after day 180. They currently store everything in S3 Standard and want to reduce storage cost without violating the 18-month retention requirement. What should they implement?

Accepted Answer

Create an S3 lifecycle policy to transition logs to Standard-IA after 30 days and to Glacier Deep Archive after 180 days. Option B is correct because an S3 lifecycle policy can automatically transition objects from S3 Standard to S3 Standard-IA after 30 days (matching the heavy-access period) and then to S3 Glacier Deep Archive after 180 days (matching the near-zero-access period). This minimizes storage costs while retaining logs for the required 18 months, as Glacier Deep Archive offers the lowest storage cost for long-term archival data.

Answer

Leave logs in S3 Standard for 18 months and add a tag for internal reporting

Answer

Immediately move all logs to Glacier Instant Retrieval and expire after 18 months

Answer

Enable versioning and rely on object lifecycle expiration to reduce costs; do not change storage classes

Question 14

A static marketing site is served through CloudFront from an S3 origin. After a product update, customers report a drop in CloudFront cache hit ratio and the CloudFront bill increases because the origin is receiving many more requests for the same JS/CSS assets. Asset URLs are versioned, but requests now include an Authorization header even though these assets are public. Which CloudFront change most directly improves the cache hit ratio for these assets?

Accepted Answer

Configure the CloudFront cache policy so Authorization is not included in the cache key, and use an origin request policy that does not forward Authorization to the S3 origin for this behavior. The drop in cache hit ratio is caused by the Authorization header being included in the cache key, which makes CloudFront treat each request as unique even when the asset URL is the same. By configuring the cache policy to exclude Authorization from the cache key and using an origin request policy that does not forward it to S3, CloudFront can serve cached responses for all users regardless of their Authorization header, restoring the cache hit ratio.

Answer

Increase the origin's max connections to handle more origin fetches

Answer

Set CloudFront minimum TTL to 0 seconds so caches expire faster and origin fetches start again

Answer

Disable CloudFront compression because Authorization headers are not cacheable when compression is enabled

Question 15

A media company runs a nightly batch job that processes video thumbnails. The batch can be interrupted at any time, and workers can resume automatically from checkpoints (a termination does not corrupt progress). The business goal is the lowest possible compute cost, and occasional interruptions are acceptable as long as the job continues automatically. Which approach is most cost-optimized?

Accepted Answer

Use EC2 Spot Instances and implement interruption handling with checkpoint-based restarts. Option B is correct because Spot Instances offer the lowest compute cost (up to 90% discount vs. On-Demand) and the checkpoint-based design ensures that interruptions are handled gracefully without data loss. The job can resume automatically from the last checkpoint, making Spot Instances ideal for fault-tolerant, interruptible batch workloads.

Answer

Run the job on On-Demand EC2 instances to avoid interruptions

Answer

Buy Reserved Instances for the entire job window because interruptions are acceptable anyway

Answer

Use Savings Plans but schedule the job only during business hours to reduce the commit cost

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

Exhibit

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

Exhibit