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

Question 1

A internal reporting portal has old unattached EBS volumes and many stale snapshots. Which two actions reduce storage cost without affecting running instances?

Accepted Answer

Delete unattached EBS volumes after verifying they are no longer needed. Unattached EBS volumes incur storage costs without providing any benefit to running instances. Deleting them after verifying they are no longer needed directly reduces these costs without affecting any active EC2 instances.

Answer

Disable CloudTrail logging

Answer

Stop all EC2 instances in the account

Question 2

A test environment has EC2 instances that are oversized based on CPU, memory, and network utilisation. Which AWS service should identify rightsizing recommendations? The design must avoid adding custom operational scripts.

Accepted Answer

AWS Compute Optimizer. AWS Compute Optimizer uses machine learning to analyze historical utilization metrics (CPU, memory, network) and generates rightsizing recommendations for EC2 instances, including instance type changes and downsizing opportunities. It operates without requiring custom scripts, as it leverages existing CloudWatch metrics and optionally the Compute Optimizer agent for enhanced memory and disk metrics.

Answer

AWS DataSync

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AWS Shield

Answer

AWS Artifact

Question 3

A media processing workflow generates analytics files that are accessed unpredictably. Some files become hot again months later. The team wants automatic storage cost optimisation without retrieval delays. What should be used? The design must avoid adding custom operational scripts.

Accepted Answer

S3 Intelligent-Tiering. S3 Intelligent-Tiering automatically moves objects between access tiers (frequent, infrequent, and archive instant access) based on changing access patterns, with no retrieval delays for hot objects and no operational overhead. This matches the unpredictable access pattern where files become hot again months later, as the service monitors access and adjusts storage class without custom scripts.

Answer

Manual monthly review and object copying

Answer

S3 Glacier Flexible Retrieval for all files

Answer

EFS One Zone for analytics files

Question 4

A dev sandbox runs for several hours each night and can be interrupted and restarted. Which EC2 purchasing option should minimize cost? The design must avoid adding custom operational scripts.

Accepted Answer

Spot Instances. Spot Instances (B) are ideal for fault-tolerant, interruptible workloads like a nightly dev sandbox because they offer significant cost savings (up to 90% off On-Demand) in exchange for being reclaimable by AWS with a 2-minute warning. Since the sandbox can be interrupted and restarted, and the design avoids custom scripts, Spot Instances can leverage native AWS features like hibernation or automatic recovery to resume work without manual intervention.

Answer

On-Demand Instances only

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Dedicated Hosts

Answer

Provisioned IOPS volumes

Question 5

A marketing site stores logs in S3. Logs are queried for 30 days, rarely accessed for one year, and then retained for compliance. What should reduce storage cost? The design must avoid adding custom operational scripts.

Accepted Answer

S3 lifecycle policy that transitions objects to lower-cost storage classes over time. S3 Lifecycle policies allow you to automatically transition objects from S3 Standard to lower-cost storage classes like S3 Standard-IA (Infrequent Access) after 30 days, then to S3 Glacier Deep Archive after one year, without custom scripts. This matches the access pattern: frequent queries for 30 days, rare access for a year, then long-term retention for compliance. The policy automates cost reduction by moving data to progressively cheaper storage as access frequency decreases.

Answer

Keep all logs in S3 Standard indefinitely

Answer

Use EBS snapshots for the logs

Answer

Move all logs immediately to S3 Glacier Deep Archive

Question 6

A internal reporting portal has old unattached EBS volumes and many stale snapshots. Which two actions reduce storage cost without affecting running instances?

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

Accepted Answer

Delete unattached EBS volumes after verifying they are no longer needed. Deleting unattached EBS volumes directly reduces storage costs without impacting running instances, as these volumes are not in use. Option D is correct because snapshot lifecycle policies automate the deletion of obsolete snapshots, eliminating manual cleanup and reducing storage costs without custom scripts.

Answer

Disable CloudTrail logging

Answer

Stop all EC2 instances in the account

Question 7

A marketing site has EC2 instances that are oversized based on CPU, memory, and network utilisation. Which AWS service should identify rightsizing recommendations? The design must avoid adding custom operational scripts.

Accepted Answer

AWS Compute Optimizer. AWS Compute Optimizer analyzes historical utilization metrics (CPU, memory, network) of EC2 instances and generates rightsizing recommendations to reduce cost without compromising performance. It uses machine learning to identify over-provisioned resources and suggests instance type changes, all without requiring custom scripts or agents.

Answer

AWS Shield

Answer

AWS DataSync

Answer

AWS Artifact

Question 8

A production internal reporting portal runs continuously on EC2 with predictable usage for the next three years. The team wants a discount while retaining some instance-family flexibility. What should they buy? The architecture review board prefers a managed AWS-native control.

Accepted Answer

Compute Savings Plan. The Compute Savings Plan offers the largest discount (up to 66%) in exchange for a commitment to a consistent amount of compute usage (measured in $/hour) for a 1- or 3-year term, while retaining flexibility across instance families, regions, and compute services (EC2, Fargate, Lambda). This matches the requirement for a discount on predictable three-year usage with instance-family flexibility, and it is a managed AWS-native purchasing option.

Answer

Spot Instances only

Answer

Dedicated Instances

Answer

S3 Intelligent-Tiering

Question 9

A media processing workflow in private subnets downloads large amounts of data from S3 through a NAT gateway. NAT data processing charges are high. What should the architect use to reduce cost? The architecture review board prefers a managed AWS-native control.

Accepted Answer

Gateway VPC endpoint for Amazon S3. A Gateway VPC endpoint for Amazon S3 allows instances in private subnets to access S3 directly over the AWS network without traversing a NAT gateway, eliminating NAT data processing charges. This is a managed AWS-native control that meets the architecture review board's preference, as it uses AWS PrivateLink and does not require any changes to the S3 bucket or client configuration beyond route table updates.

Answer

S3 Object Lambda

Answer

AWS Shield Advanced

Answer

A larger NAT gateway

Question 10

A risk simulation workload uses CloudWatch Logs heavily. Retaining all debug logs forever is increasing costs. What should be configured? The architecture review board prefers a managed AWS-native control.

Accepted Answer

CloudWatch Logs retention policies per log group. CloudWatch Logs retention policies allow you to set per-log-group expiration rules (e.g., 30 days, 90 days) to automatically delete old log events, directly reducing storage costs for debug logs that are no longer needed. This is a managed, AWS-native control that requires no custom scripts or external tools, aligning with the architecture review board's preference.

Answer

AWS Config aggregation

Answer

CloudWatch detailed monitoring on all instances

Answer

Route 53 health checks

Question 11

A dev sandbox runs for several hours each night and can be interrupted and restarted. Which EC2 purchasing option should minimize cost? The architecture review board prefers a managed AWS-native control.

Accepted Answer

Spot Instances. Spot Instances are ideal for fault-tolerant, interruptible workloads like a nightly dev sandbox because they offer up to 90% cost savings over On-Demand. Since the job can be interrupted and restarted, Spot Instances provide the lowest cost while still being a fully managed AWS-native option.

Answer

On-Demand Instances only

Answer

Dedicated Hosts

Answer

Provisioned IOPS volumes

Question 12

A production log archive runs continuously on EC2 with predictable usage for the next three years. The team wants a discount while retaining some instance-family flexibility. What should they buy? The architecture review board prefers a managed AWS-native control.

Accepted Answer

Compute Savings Plan. A Compute Savings Plan offers the lowest prices on EC2 compute usage (up to 66% off On-Demand) in exchange for a 1- or 3-year commitment, while allowing instance-family flexibility across any region, OS, or tenancy. This matches the predictable three-year workload and the team's requirement for instance-family flexibility, and it is a managed AWS-native offering (no manual reservation management).

Answer

S3 Intelligent-Tiering

Answer

Dedicated Instances

Answer

Spot Instances only

Question 13

A risk simulation workload in private subnets downloads large amounts of data from S3 through a NAT gateway. NAT data processing charges are high. What should the architect use to reduce cost? The architecture review board prefers a managed AWS-native control.

Accepted Answer

Gateway VPC endpoint for Amazon S3. A Gateway VPC Endpoint for Amazon S3 allows instances in private subnets to access S3 directly over the AWS network without traversing a NAT gateway, eliminating NAT data processing charges. This is a managed AWS-native control that meets the architecture review board's preference, as it uses AWS PrivateLink to route traffic to S3 without requiring an internet gateway or NAT.

Answer

A larger NAT gateway

Answer

S3 Object Lambda

Answer

AWS Shield Advanced

Question 14

A company runs a SaaS application with highly unpredictable database load — it may receive zero queries for hours, then spike to thousands of queries per second briefly. The company wants to minimize database costs while handling all load levels without manual scaling. Which solution is MOST cost-effective?

Accepted Answer

Amazon Aurora Serverless v2 — scales automatically from minimum capacity during idle to maximum during spikes. Amazon Aurora Serverless v2 automatically scales database capacity based on actual load. It scales from a minimum of 0.5 ACUs during quiet periods to up to 128 ACUs during spikes within seconds. You pay only for the ACUs consumed — idle periods cost near-minimum.

Aurora Provisioned requires pre-provisioning capacity for peak load, incurring full instance costs regardless of actual utilization. Even with Auto Scaling, the primary instance has a minimum provisioned capacity that runs at full cost during idle periods.

Answer

Amazon Aurora Provisioned with Auto Scaling to add and remove read replicas

Answer

Amazon RDS MySQL with scheduled stop/start to save costs during predictable off-hours

Answer

Amazon DynamoDB with on-demand capacity mode — scales to any traffic level with no minimum cost

Question 15

A company runs a web application on Amazon EC2 instances behind an Application Load Balancer. The workload is predictable during business hours but has low usage at night. Which three options can reduce costs without compromising performance? (Choose three.)

Accepted Answer

Configure a scheduled auto scaling policy to reduce the number of instances during off-peak hours.. To reduce costs without compromising performance for a web application with predictable peak and low usage:
1.  **Scheduled Auto Scaling:** Configuring a scheduled Auto Scaling policy allows you to automatically reduce the number of EC2 instances during known off-peak hours (e.g., nights and weekends) and scale them back up for business hours. This directly reduces hourly instance costs when demand is low without impacting performance during peak times.
2.  **Dynamic Scaling based on CPU Utilization:** Implementing a dynamic scaling policy (e.g., target tracking based on CPU utilization) ensures that the EC2 fleet automatically scales in when demand (and thus CPU usage) is low, and scales out when demand increases. This right-sizes the fleet to current needs, optimizing costs while maintaining performance.
3.  **Compute Savings Plans:** Purchasing Compute Savings Plans provides significant discounts on EC2 usage (and other compute services) in exchange for a 1- or 3-year commitment to a consistent spend. This is ideal for covering the predictable baseline workload during business hours, reducing the effective hourly cost of those instances without affecting their performance or availability.

Answer

Use EC2 Spot Instances for the entire workload to achieve the lowest possible cost.

Answer

Use a single large EC2 instance to handle all traffic, reducing the number of running instances.

Answer

Replace the Application Load Balancer with a Network Load Balancer, which is cheaper per hour.