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

Question 1

A test environment has EC2 instances that are oversized based on CPU, memory, and network utilisation. Which AWS service should identify rightsizing recommendations?

Accepted Answer

AWS Compute Optimizer. AWS Compute Optimizer uses machine learning to analyze historical utilization metrics (CPU, memory, network, and storage) and provides rightsizing recommendations for EC2 instances, including over-provisioned resources. It helps reduce costs by suggesting instance types or sizes that better match actual workload demands.

Answer

AWS DataSync

Answer

AWS Shield

Answer

AWS Artifact

Question 2

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?

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. This is ideal for unpredictable access where some files become hot again months later, as it optimizes storage costs without manual intervention or retrieval latency.

Answer

Manual monthly review and object copying

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S3 Glacier Flexible Retrieval for all files

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EFS One Zone for analytics files

Question 3

A dev sandbox runs for several hours each night and can be interrupted and restarted. Which EC2 purchasing option should minimize cost?

Accepted Answer

Spot Instances. Spot Instances can be interrupted and restarted, making them ideal for fault-tolerant workloads like a nightly dev sandbox. They offer significant cost savings (up to 90% off On-Demand) because they use spare AWS EC2 capacity, which aligns perfectly with the scenario's tolerance for interruption.

Answer

On-Demand Instances only

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Dedicated Hosts

Answer

Provisioned IOPS volumes

Question 4

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?

Accepted Answer

Compute Savings Plan. The Compute Savings Plan (C) is correct because it offers a 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 allowing flexibility to change instance families, sizes, OS, tenancy, and even regions within EC2, Fargate, and Lambda. This matches the requirement of predictable usage for three years with instance-family flexibility, unlike Reserved Instances which lock to a specific instance family.

Answer

S3 Intelligent-Tiering

Answer

Dedicated Instances

Answer

Spot Instances only

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?

Accepted Answer

S3 lifecycle policy that transitions objects to lower-cost storage classes over time. An S3 Lifecycle policy automates the transition of objects from S3 Standard (frequently accessed) to lower-cost storage classes like S3 Standard-IA (infrequent access) after 30 days, then to S3 Glacier Deep Archive for long-term compliance retention. This matches the access pattern: frequent queries for 30 days, rare access for a year, then archival storage, minimizing cost without manual intervention.

Answer

Keep all logs in S3 Standard indefinitely

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Use EBS snapshots for the logs

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Move all logs immediately to S3 Glacier Deep Archive

Question 6

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?

Accepted Answer

Gateway VPC endpoint for Amazon S3. A Gateway VPC endpoint for Amazon S3 allows instances in private subnets to access S3 directly via the AWS network, bypassing the NAT gateway entirely. This eliminates NAT data processing charges (per GB) for S3 traffic, which can be significant for large data downloads. The endpoint is free to use and routes traffic through AWS's private backbone, not the internet.

Answer

A larger NAT gateway

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S3 Object Lambda

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AWS Shield Advanced

Question 7

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?

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 and writes you perform. This eliminates the need to provision capacity for peak traffic, avoiding costs during long idle periods and reducing operational overhead from capacity management.

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Reserved capacity for maximum daily traffic

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Provisioned capacity set for peak traffic

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Global tables in every Region

Question 8

A test environment runs on x86 EC2 instances and uses open-source software with no architecture-specific licensing restriction. What should be evaluated to reduce compute cost?

Accepted Answer

AWS Graviton-based instances after performance testing. AWS Graviton-based instances (e.g., M6g, C6g) use Arm-based custom AWS silicon, offering up to 40% better price-performance compared to comparable x86 instances for many workloads. Since the test environment runs open-source software with no architecture-specific licensing restrictions, migrating to Graviton after performance testing can significantly reduce compute costs without compatibility issues.

Answer

Cross-Region data replication for all data

Answer

io2 Block Express volumes for all instances

Answer

Dedicated Hosts by default

Question 9

A media processing workflow uses CloudWatch Logs heavily. Retaining all debug logs forever is increasing costs. What should be configured?

Accepted Answer

CloudWatch Logs retention policies per log group. CloudWatch Logs retention policies per log group allow you to set an expiration time (e.g., 30 days) after which log events are automatically deleted. This directly reduces storage costs by preventing debug logs from accumulating indefinitely, without affecting other monitoring or routing functions.

Answer

Route 53 health checks

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CloudWatch detailed monitoring on all instances

Answer

AWS Config aggregation

Question 10

A dev sandbox 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?

Accepted Answer

Whether one NAT gateway per AZ is sufficient for the required private subnets. The question states that only one private subnet per AZ needs outbound internet access, so using two NAT gateways per AZ is likely over-provisioned and costly. The architect should first review whether one NAT gateway per AZ is sufficient, as NAT gateways are billed per hour and per gigabyte of data processed, and reducing from two to one per AZ can cut costs without sacrificing availability. This aligns with the cost-optimized design principle of right-sizing resources to actual demand.

Answer

Disabling route tables

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

Answer

Moving all workloads to public subnets

Question 11

A log archive serves infrequently accessed user documents that must be available immediately when requested. Which S3 storage class is likely the best cost fit?

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 workload involves infrequently accessed data that requires immediate retrieval (millisecond latency). Standard-IA offers lower storage cost than S3 Standard while maintaining high durability and low-latency access, and One Zone-IA provides even lower cost for data that can tolerate a single-AZ failure. Both classes meet the 'available immediately' requirement, unlike Glacier tiers which have retrieval delays.

Answer

Instance store volumes

Answer

S3 Standard for all objects

Answer

S3 Glacier Deep Archive

Question 12

A marketing site has EC2 instances that are oversized based on CPU, memory, and network utilisation. Which AWS service should identify rightsizing recommendations?

Accepted Answer

AWS Compute Optimizer. AWS Compute Optimizer analyzes historical utilization metrics (CPU, memory, network, and storage) from CloudWatch and uses machine learning to identify over-provisioned or under-provisioned EC2 instances. It generates actionable rightsizing recommendations, including instance type changes, to optimize cost and performance. This directly addresses the scenario of oversized EC2 instances.

Answer

AWS Shield

Answer

AWS DataSync

Answer

AWS Artifact

Question 13

A risk simulation workload 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?

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 access) based on changing access patterns, without any retrieval delays. This handles the unpredictable access described—files that become hot again months later—by keeping them in the archive instant access tier until access resumes, then promoting them instantly. It optimizes storage costs automatically without manual intervention or cold retrieval waits.

Answer

Manual monthly review and object copying

Answer

S3 Glacier Flexible Retrieval for all files

Answer

EFS One Zone for analytics files

Question 14

A batch analytics job 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 are ideal for fault-tolerant, interruptible batch workloads because they offer significant cost savings (up to 90% off On-Demand pricing) by using spare EC2 capacity. Since the job can be interrupted and restarted, it can handle Spot Instance reclaimations without requiring custom operational scripts—AWS handles the interruption notification and automatic instance termination, and the job's restart logic can be built into the application or orchestration layer (e.g., AWS Batch).

Answer

On-Demand Instances only

Answer

Dedicated Hosts

Answer

Provisioned IOPS volumes

Question 15

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 design must avoid adding custom operational scripts.

Accepted Answer

Compute Savings Plan. Compute Savings Plans offer the lowest prices on EC2 instance usage (up to 66% off On-Demand) in exchange for a 1- or 3-year commitment, while allowing flexibility across instance families, sizes, OS, and regions. This matches the requirement for a discount on predictable, continuous usage without locking into a specific instance type, and requires no custom scripts.

Answer

Spot Instances only

Answer

Dedicated Instances

Answer

S3 Intelligent-Tiering