SAA-C03 Design Cost-Optimized Architectures Practice Test 13 — 15 Questions

Question 1

A internal reporting portal serves infrequently accessed user documents that must be available immediately when requested. Which S3 storage class is likely the best cost fit? The architecture review board prefers a managed AWS-native control.

Accepted Answer

S3 Standard-IA or S3 One Zone-IA depending on resilience requirements. S3 Standard-IA or S3 One Zone-IA is the best cost fit because the data is infrequently accessed but requires immediate availability when requested. These storage classes offer lower storage costs than S3 Standard while providing millisecond first-byte latency, meeting the 'immediately available' requirement. The choice between Standard-IA and One Zone-IA depends on the resilience needs (e.g., multi-AZ vs. single-AZ durability).

Answer

Instance store volumes

Answer

S3 Glacier Deep Archive

Answer

S3 Standard for all objects

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 architecture review board prefers a managed AWS-native control.

Accepted Answer

AWS Compute Optimizer. AWS Compute Optimizer is a managed service that uses machine learning to analyze historical utilization metrics (CPU, memory, network, and storage) and provides rightsizing recommendations for EC2 instances. It identifies over-provisioned resources and suggests instance types that better match workload requirements, directly addressing the oversized EC2 instances in the test environment.

Answer

AWS DataSync

Answer

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 architecture review board prefers a managed AWS-native control.

Accepted Answer

S3 Intelligent-Tiering. S3 Intelligent-Tiering is the correct choice because it automatically moves objects between access tiers (frequent, infrequent, and archive instant retrieval) based on changing access patterns, without any retrieval delays for hot objects. This matches the unpredictable access pattern where files may become hot again months later, and it is a fully managed AWS-native solution that optimizes storage costs automatically.

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 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 5

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 6

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 architecture review board prefers a managed AWS-native control.

Accepted Answer

S3 lifecycle policy that transitions objects to lower-cost storage classes over time. Option A is correct because an S3 Lifecycle policy is a managed AWS-native feature that automatically transitions objects to lower-cost storage classes (e.g., S3 Standard-IA after 30 days, S3 Glacier Instant Retrieval or S3 Glacier Flexible Retrieval after one year) based on age, reducing storage costs while maintaining compliance. This aligns with the access pattern: frequent queries for 30 days, rare access for a year, then long-term retention. It avoids manual intervention and optimizes cost without sacrificing availability or retrieval needs.

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 7

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 8

A batch analytics job has unpredictable DynamoDB traffic with long idle periods and occasional spikes. Which capacity mode should minimize operational overhead and avoid paying for idle provisioned capacity? The architecture review board prefers a managed AWS-native control.

Accepted Answer

DynamoDB on-demand capacity mode. DynamoDB on-demand capacity mode automatically scales to handle unpredictable traffic spikes and idle periods, charging only for the reads/writes you perform. This eliminates the need to provision capacity, reducing operational overhead and avoiding costs for idle provisioned capacity, aligning with the architecture review board's preference for a managed AWS-native control.

Answer

Reserved capacity for maximum daily traffic

Answer

Provisioned capacity set for peak traffic

Answer

Global tables in every Region

Question 9

A internal reporting portal has old unattached EBS volumes and many stale snapshots. Which two actions reduce storage cost without affecting running instances? The architecture review board prefers a managed AWS-native control.

Accepted Answer

Delete unattached EBS volumes after verifying they are no longer needed. Option C is correct because unattached EBS volumes incur storage costs without providing any benefit to running instances. Deleting them after verification directly reduces costs while having zero impact on running workloads. Option D is correct because snapshot lifecycle policies automate the deletion of obsolete snapshots based on age or count, eliminating manual cleanup and reducing storage costs without affecting running instances.

Answer

Disable CloudTrail logging

Answer

Stop all EC2 instances in the account

Question 10

A company stores millions of objects in Amazon S3. Access patterns are completely unpredictable — some objects are frequently accessed, others rarely. Objects range from 4 KB to 50 MB. The company wants to minimize storage costs automatically without managing lifecycle rules. Which storage class should a solutions architect recommend?

Accepted Answer

S3 Intelligent-Tiering — it automatically moves objects between tiers based on access patterns. S3 Intelligent-Tiering monitors access patterns and automatically moves objects between access tiers — Frequent Access, Infrequent Access, and optional Archive tiers — based on actual usage. It requires no management or lifecycle rules.

Important: Intelligent-Tiering charges a small monitoring fee per object per month. For objects under 128 KB, this fee may exceed the storage savings. With objects ranging from 4 KB to 50 MB and unpredictable access patterns, Intelligent-Tiering is the recommended answer — AWS explicitly recommends it for unknown access patterns where object size averages above 128 KB.

Answer

S3 Standard — it is the default and handles all access patterns equally

Answer

S3 Standard-IA — it automatically detects infrequent access and reduces cost

Answer

S3 One Zone-IA — it is the cheapest option with fast retrieval

Question 11

A company runs EC2 workloads including web servers (m5.large), batch jobs (c5.xlarge), and a data processing service that will migrate from r5 to r6i instances within 6 months. The company wants to commit to 1 year to reduce costs but needs flexibility for the planned instance family migration. Which purchasing option provides the GREATEST savings while accommodating the change?

Accepted Answer

Compute Savings Plans with a 1-year term commitment. Compute Savings Plans automatically apply to any EC2 instance regardless of family, size, region, OS, or tenancy — including both r5 and r6i. When the data processing service migrates from r5 to r6i, the Compute Savings Plan continues to apply without any action required.

EC2 Instance Savings Plans lock to a specific instance family in a specific region. When the workload migrates from r5 to r6i, the EC2 Instance Savings Plan for r5 no longer applies — leaving the r6i workload billed at On-Demand rates.

Answer

Standard Reserved Instances for each instance type with a 1-year term

Answer

EC2 Instance Savings Plans for the r5 instance family with a 1-year term

Answer

Convertible Reserved Instances for all instance types with a 1-year term

Question 12

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 13

A company is migrating its on-premises workloads to AWS and wants to optimize costs. Which three strategies should the company implement to achieve a cost-optimized architecture? (Choose three.)

Accepted Answer

Use Reserved Instances or Savings Plans for predictable workloads to reduce costs compared to On-Demand pricing.. Reserved Instances or Savings Plans provide significant discounts (up to 72%) over On-Demand pricing for predictable workloads by committing to a specific usage term (1 or 3 years). This directly reduces compute costs for steady-state applications, making it a core cost-optimization strategy.

Answer

Provision additional EC2 instances to handle peak load at all times, ensuring maximum performance.

Answer

Deploy all resources in a single Availability Zone to minimize data transfer costs.

Answer

Store all data in Amazon S3 Standard storage class to avoid any data retrieval costs.

Question 14

A solutions architect is designing a cost-optimized data storage solution for a large dataset that is accessed infrequently but must be retained for compliance for 7 years. Which three actions should the architect take to minimize costs? (Choose three.)

Accepted Answer

Use Amazon S3 lifecycle policies to transition data from S3 Standard to S3 Glacier Deep Archive after 30 days.. Amazon S3 lifecycle policies allow you to define rules that automatically transition objects to colder storage tiers like S3 Glacier Deep Archive after a specified period. This approach minimizes costs by keeping data in S3 Standard only for the initial 30 days when it might be accessed, then moving it to the lowest-cost storage class for the remaining compliance period. S3 Intelligent-Tiering automatically optimizes costs by monitoring access patterns and moving data between frequent, infrequent, and archive access tiers without manual intervention. S3 Object Lock in compliance mode prevents any user, including the root user, from deleting or overwriting objects during the retention period, ensuring regulatory compliance.

Answer

Store all data in Amazon EBS gp2 volumes attached to an EC2 instance for low-latency access.

Answer

Store the data in Amazon S3 Glacier Deep Archive immediately after creation.

Answer

Replicate all data to a second AWS Region using S3 Cross-Region Replication to ensure durability.

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

Implement a scaling policy based on CPU utilization to right-size the fleet dynamically.. Compute Savings Plans offer significant discounts (up to 66%) compared to On-Demand pricing in exchange for a commitment to a consistent amount of compute usage (measured in $/hour) over a 1- or 3-year term. They apply to EC2 instances, AWS Fargate, and Lambda, making them ideal for covering the predictable baseline workload during business hours. This reduces costs without affecting performance because the instances continue to run at full capacity.

Answer

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

Answer

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

Answer

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