SAA-C03 Design Cost-Optimized Architectures Practice Test 9 — 15 Questions

Question 1

A log archive 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.

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 eliminates storage costs for volumes that are not in use, and since they are not attached to any running instance, this action does not affect running instances. Option D is correct because applying snapshot lifecycle policies (e.g., using Amazon Data Lifecycle Manager) automates the expiration of obsolete snapshots, reducing storage costs without impacting running instances. Both actions are managed AWS-native controls, aligning with the architecture review board's preference.

Answer

Stop all EC2 instances in the account

Answer

Disable CloudTrail logging

Question 2

A marketing site runs on x86 EC2 instances and uses open-source software with no architecture-specific licensing restriction. What should be evaluated to reduce compute cost? The architecture review board prefers a managed AWS-native control.

Accepted Answer

AWS Graviton-based instances after performance testing. AWS Graviton-based instances use ARM-based custom processors that offer up to 40% better price-performance compared to comparable x86 instances for many workloads. Since the marketing site runs open-source software with no architecture-specific licensing restrictions, migrating to Graviton after performance testing can significantly reduce compute costs while leveraging a managed AWS-native control (e.g., EC2 Auto Scaling groups with Graviton instance types).

Answer

Cross-Region data replication for all data

Answer

io2 Block Express volumes for all instances

Answer

Dedicated Hosts by default

Question 3

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 4

A batch analytics job currently uses two NAT gateways in each of three Availability Zones, but only one private subnet per AZ needs outbound internet access. What should the architect review first? The architecture review board prefers a managed AWS-native control.

Accepted Answer

Whether one NAT gateway per AZ is sufficient for the required private subnets. The architecture currently uses two NAT gateways per AZ, but only one private subnet per AZ requires outbound internet access. Since a single NAT gateway in an AZ can serve all private subnets in that AZ via the route table, the first step is to verify whether one NAT gateway per AZ is sufficient for the required throughput and availability. This aligns with cost optimization by eliminating unnecessary NAT gateway hourly charges and data processing fees.

Answer

Replacing every NAT gateway with an internet gateway attached to private subnets

Answer

Disabling route tables

Answer

Moving all workloads to public subnets

Question 5

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 6

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 7

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 8

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 9

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 10

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. 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 11

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 12

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 13

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. 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 14

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 15

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