SAA-C03 Design Cost-Optimized Architectures — 15 Questions

Question 1

A company runs a stateless web application on EC2 instances behind an Application Load Balancer. The traffic is highly predictable, peaking during business hours and dropping significantly at night. Which strategy offers the most cost-effective solution for this workload?

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

Accepted Answer

Use Reserved Instances for base capacity and Auto Scaling with On-Demand instances for peaks.. The explanation correctly identifies that Reserved Instances should cover the base load and Auto Scaling should handle the peaks. However, the 'COMMON TRAP' note incorrectly describes the correct strategy as a 'trap' instead of the recommended solution.

Answer

Provision On-Demand instances sized for peak capacity 24/7.

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Migrate the entire application to AWS Lambda functions.

Answer

Use Spot Instances for the entire fleet to maximize savings.

Question 2

A startup is migrating a large database to Amazon RDS. The database has an inconsistent workload with high activity during the day and very low activity at night. Which TWO actions will optimize storage and compute costs? (Select TWO.)

Accepted Answer

Use Amazon RDS General Purpose SSD (gp3) storage.. Option B is correct because Amazon RDS General Purpose SSD (gp3) storage delivers baseline performance of 3,000 IOPS with the ability to provision additional IOPS and throughput independently of storage capacity, so it can absorb the daytime peaks without paying for over-provisioned io1 capacity around the clock. Option C is correct because stopping an RDS instance during the low-activity night hours eliminates compute charges for that period (you pay only for provisioned storage and backups while stopped), which directly reduces compute cost for a workload with a predictable nightly lull. Option A is not appropriate because io1 Provisioned IOPS SSD sized for maximum load is the most expensive storage choice and wastes money during the long low-activity periods. Option D is wrong because a larger instance type raises cost rather than optimizing it, and it is unnecessary when the workload is intermittent. Option E is wrong because Multi-AZ doubles the instance and storage cost by maintaining a synchronous standby, which is unjustified for non-production environments and does nothing to optimize storage or compute spend.

Answer

Provision Provisioned IOPS SSD (io1) storage to handle the maximum expected load.

Answer

Upgrade to a larger instance type to ensure performance never drops.

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Enable Multi-AZ deployment for all non-production database environments.

Question 3

Refer to the exhibit. A solutions architect is reviewing a lifecycle policy for an S3 bucket containing application logs. The company requires these logs to be retained for seven years for compliance but rarely accesses them. A retrieval time of 12 hours is acceptable. Which statement best evaluates the cost-effectiveness of this configuration?

Accepted Answer

The policy is optimal because Glacier Deep Archive offers the lowest storage cost for long-term retention.. The Amazon S3 Glacier Deep Archive storage class is the lowest-cost storage class in AWS, designed for data that is rarely accessed and can tolerate a retrieval time of 12 hours. By implementing a lifecycle policy to transition objects after 90 days, the company significantly reduces monthly storage fees while maintaining data durability across multiple Availability Zones.

Answer

The policy should use S3 Intelligent-Tiering to automate cost savings without manual lifecycle rules.

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The policy should transition objects to S3 One Zone-IA to reduce costs by 20% over standard Glacier.

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The policy is inefficient because Glacier Flexible Retrieval offers faster access at the same price point.

Question 4

A solutions architect needs to design a cost-optimized storage solution for a media company. The company has 100 TB of data that is accessed frequently for the first 30 days, then rarely accessed. However, when accessed after 30 days, the data must be available immediately. Which strategy is most cost-effective?

Accepted Answer

Configure S3 Intelligent-Tiering for all objects upon upload.. S3 Intelligent-Tiering automatically moves objects between access tiers based on changing access patterns, charging a small monitoring fee per object. For data that is frequently accessed for 30 days and then rarely accessed, it will transition objects to the Infrequent Access tier after 30 days of no access, providing immediate retrieval with no retrieval fees. This eliminates the need to guess access patterns or manage lifecycle rules, and it is cost-effective because you pay only for the tiers actually used, with no early deletion penalties or retrieval charges.

Answer

Store all data in S3 Standard for the entire duration.

Answer

Use S3 Lifecycle policies to move data to S3 Standard-IA after 30 days.

Answer

Move data to S3 Glacier Instant Retrieval after 30 days.

Question 5

A company wants to optimize its S3 costs. They have many buckets with millions of objects and are unsure which objects are being accessed. Which TWO AWS tools or features can help identify and automate cost savings? (Select TWO.)

Accepted Answer

Amazon S3 Storage Lens. Amazon S3 Storage Lens (C) is correct because it provides organization-wide visibility into storage usage and activity metrics across millions of objects, including access patterns, and it delivers actionable recommendations and cost-efficiency insights that help identify savings opportunities. Amazon S3 Intelligent-Tiering (D) is correct because it automatically moves objects between access tiers based on changing access patterns, so for buckets with millions of objects whose access is unknown, it eliminates retrieval fees while automating cost savings without manual lifecycle rules. The unmarked options do not fit: AWS Trusted Advisor (A) offers general best-practice checks but lacks granular, object-level S3 access analytics; Amazon S3 Inventory (B) only produces scheduled reports of object metadata and storage class, not access-pattern analysis or automated tiering; and AWS Budgets (E) only tracks and alerts on spending against thresholds, without identifying which objects are accessed or automating storage-cost optimization.

Answer

AWS Trusted Advisor

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Amazon S3 Inventory

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AWS Budgets

Question 6

A company has a variety of compute resources, including EC2 instances, Lambda functions, and Fargate tasks. They want to commit to a consistent amount of compute usage for a 3-year term to reduce costs. Which option provides the most flexibility?

Accepted Answer

Compute Savings Plans. Compute Savings Plans provide the greatest flexibility because they apply automatically to EC2, Lambda, and Fargate usage regardless of region, instance family, or operating system. This allows the company to change their compute technology or move workloads between services while still benefiting from the significant 3-year commitment discount.

Answer

Standard Reserved Instances

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EC2 Instance Savings Plans

Answer

Convertible Reserved Instances

Question 7

A company hosts a static website on Amazon S3 and serves it globally. They want to reduce the cost of data transfer while improving performance for users in Asia and Europe. Which TWO actions should they take? (Select TWO.)

Accepted Answer

Deploy an Amazon CloudFront distribution in front of the S3 bucket.. Option B is correct because Amazon CloudFront caches the static website content at edge locations worldwide, so users in Asia and Europe retrieve objects from nearby points of presence instead of from the origin S3 bucket, which reduces origin data transfer costs and lowers latency. Option E is correct because CloudFront Price Class 200 or All includes edge locations in Asia and Europe (Price Class 100 covers only North America and Europe), ensuring the distribution actually serves those user populations from regional edge locations rather than routing them to more distant ones. Option A is incorrect because S3 Transfer Acceleration speeds up uploads to a bucket using AWS edge locations and does not reduce data transfer cost or improve global download performance for a static website. Option C is incorrect because replicating the bucket to Asia and Europe duplicates storage and does not by itself route users to the nearest copy without additional DNS or CDN logic, and it increases rather than reduces cost. Option D is incorrect because an Application Load Balancer operates at the regional level for HTTP/HTTPS traffic to targets such as EC2 instances and cannot distribute S3 static website traffic across global regions.

Answer

Enable S3 Transfer Acceleration for the bucket.

Answer

Replicate the S3 bucket to regions in Asia and Europe.

Answer

Use an Application Load Balancer to distribute traffic between regions.

Question 8

A company is using Amazon EFS to provide shared storage for a fleet of Linux instances. The data is accessed frequently for two weeks, but then it is rarely accessed for months. How can the architect minimize storage costs?

Accepted Answer

Enable EFS Lifecycle Management to move data to the Infrequent Access tier.. EFS Lifecycle Management automatically moves files that haven't been accessed for a set period (e.g., 30 days) to the EFS Infrequent Access (IA) storage class. EFS IA costs significantly less than the Standard storage class, allowing the company to save money on long-term storage without changing the application's access methods.

Answer

Create a script to move old files from EFS to an S3 Glacier bucket.

Answer

Use EFS Provisioned Throughput to optimize data transfer speeds.

Answer

Migrate the data to an Amazon EBS volume with Multi-Attach enabled.

Question 9

A company has a web application that experiences sudden, unpredictable spikes in traffic. The application uses an Amazon DynamoDB table. The company wants to optimize costs while ensuring that the application can handle these spikes without throttling. Which DynamoDB capacity mode should the company choose?

Accepted Answer

On-Demand capacity mode.. DynamoDB On-Demand capacity mode is ideal for workloads with unpredictable or spiky traffic. It automatically scales to handle throughput requirements and charges only for the actual read and write requests performed. This eliminates the need for manual capacity planning and prevents over-provisioning costs associated with Provisioned Capacity mode during low-traffic periods.

Answer

Provisioned capacity with Auto Scaling.

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Reserved Capacity.

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Provisioned capacity with a high fixed limit.

Question 10

An e-commerce company uses Amazon CloudFront to deliver its website content globally. The origin is an Application Load Balancer (ALB) in the us-east-1 Region. The company wants to reduce the data transfer costs from the ALB to CloudFront. What should the company do?

Accepted Answer

Enable CloudFront 'Origin Shield'.. Data transfer from an Application Load Balancer to Amazon CloudFront is already free of charge. Therefore, you do not incur charges for data transferred out from the ALB to CloudFront. Candidates often get confused and look for architectural changes to reduce data transfer costs that do not exist.

Answer

Use a VPC Peering connection between the ALB and CloudFront.

Answer

Ensure the ALB is the origin for the CloudFront distribution.

Answer

Implement AWS Global Accelerator.

Question 11

A company runs a high-performance computing (HPC) workload that requires high-throughput, low-latency shared storage. The workload is temporary and only runs for 4 hours a day. The data is backed up on S3. Which storage solution provides the best performance at the lowest cost for this scenario?

Accepted Answer

Amazon FSx for Lustre using Scratch 2 deployment.. Amazon FSx for Lustre is optimized for HPC workloads. By using a 'Scratch' file system, the company gets high-performance temporary storage at a lower cost than 'Persistent' storage. Since the workload is only 4 hours a day and data is already in S3, Scratch storage is the most cost-effective way to achieve the required throughput.

Answer

Amazon Elastic File System (EFS) with Provisioned Throughput.

Answer

Amazon FSx for Lustre using Persistent 2 deployment.

Answer

Amazon S3 using S3 Transfer Acceleration.

Question 12

A solutions architect is designing a storage strategy for a media company that stores millions of 5 MB images. The images are accessed frequently during the first 30 days, but access patterns become unpredictable after that period. Some images might be accessed daily, while others might not be accessed for months. Which TWO solutions provide the most cost-effective storage? (Select TWO.)

Accepted Answer

Use S3 Intelligent-Tiering for objects after the initial 30-day frequent access period.. Option D is correct because S3 Standard is the appropriate storage class for the first 30 days when the images are accessed frequently, providing low latency and high throughput without early-deletion or retrieval charges. Option B is correct because after 30 days the access patterns become unpredictable, and S3 Intelligent-Tiering automatically moves objects between frequent and infrequent access tiers based on changing access patterns, avoiding retrieval fees while optimizing cost. Option A is wrong because S3 Standard-IA has a 30-day minimum storage duration and per-GB retrieval charges, making it more expensive than S3 Standard for objects accessed frequently during the first 30 days. Option C is wrong because S3 Glacier Deep Archive is designed for long-term archival with retrieval times of 12 hours, which is unsuitable for images that might be accessed daily. Option E is wrong because S3 One Zone-IA stores data in a single Availability Zone and still imposes retrieval charges and a 30-day minimum, and it does not adapt to unpredictable access patterns like Intelligent-Tiering does.

Answer

Store all images in S3 Standard-Infrequent Access (S3 Standard-IA) from day one.

Answer

Configure an S3 Lifecycle policy to move objects to S3 Glacier Deep Archive after 30 days.

Answer

Implement an S3 Lifecycle policy to transition objects to S3 One Zone-IA after 30 days.

Question 13

A data processing company runs large-scale batch jobs that are fault-tolerant and can be paused and restarted without data loss. These jobs take approximately 6 hours to complete and run twice a week. What is the most cost-optimized EC2 instance purchasing option for this workload?

Accepted Answer

Spot Instances. Spot Instances are the most cost-effective choice for fault-tolerant, flexible batch processing workloads, offering up to 90% savings over On-Demand prices. Since the application can handle interruptions and resume progress, the lower cost of Spot Instances outweighs the risk of the instances being reclaimed by AWS during the job execution.

Answer

On-Demand Instances

Answer

Dedicated Hosts

Answer

Reserved Instances

Question 14

An architect is reviewing the data transfer costs for a global application. The application uses an Application Load Balancer (ALB) to distribute traffic to EC2 instances across three Availability Zones. Large amounts of data are also synchronized between the instances. Which THREE actions will reduce data transfer costs? (Select THREE.)

Accepted Answer

Deploy Amazon CloudFront in front of the Application Load Balancer.. To reduce data transfer costs, the architect should: 1) Use CloudFront to cache content (A), 2) Keep traffic within the same AZ (B), and 3) Use Private IP addresses for inter-instance communication instead of Public/Elastic IPs. Option C is the opposite of the correct strategy.

Answer

Use Public IP addresses for all communication between EC2 instances.

Answer

Enable Cross-Zone Load Balancing on the Application Load Balancer.

Answer

Use AWS Direct Connect for all inter-region data transfers.

Answer

Route traffic through a Transit Gateway to consolidate data paths.

Question 15

A company has a high-traffic web application that uses an Application Load Balancer (ALB) and EC2 instances. The company wants to reduce costs while maintaining high availability. Which TWO actions should the architect take?

Accepted Answer

Purchase Compute Savings Plans for the EC2 compute resources.. Option A is correct because Compute Savings Plans apply to EC2 instance usage (and also Fargate and Lambda) and provide up to 72% savings over On-Demand in exchange for a 1- or 3-year hourly spend commitment, directly reducing compute costs while the instances remain highly available behind the ALB. Option C is correct because configuring Auto Scaling with target tracking on CPU utilization (e.g., an average of 50%) dynamically adds instances during peak traffic and removes them during lulls, so the company pays only for capacity it actually needs while maintaining availability across multiple AZs. Option B is not appropriate because Network Load Balancers are not inherently cheaper for this use case and lack ALB Layer 7 features such as path/host-based routing and HTTP health checks that a web application typically relies on. Option D is wrong because a single EC2 proxy instance is a single point of failure and cannot match the ALB's elasticity or availability. Option E is wrong because consolidating all instances into one Availability Zone eliminates AZ redundancy and violates the high-availability requirement.

Answer

Switch the ALB to a Network Load Balancer to reduce fixed costs.

Answer

Replace the ALB with a single large EC2 instance to act as a proxy.

Answer

Move all EC2 instances to a single Availability Zone.