SAA-C03 Design Cost-Optimized Architectures Practice Test 7 — 15 Questions

Question 1

A startup runs a nightly analytics job on a single Amazon RDS for PostgreSQL database. The job runs for about 90 minutes, and the team has confirmed that the instance is completely idle for the remaining 22.5 hours each day. The database must retain its data between runs and must be reachable at a fixed DNS endpoint. Which approach reduces cost the most while meeting these requirements?

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

Accepted Answer

Stop the DB instance each night after the job and start it again before the next run. Stopping an RDS DB instance during the long idle window eliminates instance-hour billing while preserving both the stored data and the endpoint that the job depends on. Because the database is idle for roughly 22.5 hours a day, this produces a far larger saving than any commitment-based discount applied to an instance that would otherwise run around the clock.

Answer

Delete the DB instance after each run and restore it from a snapshot before the next run

Answer

Migrate the workload to Aurora Serverless v2 and keep the minimum capacity at zero

Answer

Purchase a 1-year All Upfront Reserved Instance for the DB instance

Question 2

A healthcare company stores medical imaging archives in an S3 bucket. The images are accessed frequently for the first 90 days after creation, then only occasionally for the next 2 years, and after 3 years they must be retained for 7 more years for compliance but are almost never accessed. The company wants to minimize storage costs while keeping the data immediately available for the first 2 years. Which S3 lifecycle configuration meets these requirements MOST cost-effectively?

Accepted Answer

Transition objects to S3 Standard-IA after 90 days, then to S3 Glacier Instant Retrieval after 2 years, and to S3 Glacier Deep Archive after 3 years.. The data has three distinct access phases: frequent for 90 days, occasional for 2 years, and almost never after 3 years. S3 Standard-IA handles the occasional phase, S3 Glacier Instant Retrieval keeps data immediately available for the 2-to-3-year window, and S3 Glacier Deep Archive minimizes cost for the long compliance tail. This combination aligns storage cost with access frequency while preserving immediate availability where required.

Answer

Transition objects to S3 Standard-IA after 90 days, then to S3 Glacier Deep Archive after 2 years.

Answer

Transition objects to S3 Standard-IA after 90 days, then to S3 Glacier Deep Archive after 3 years.

Answer

Transition objects to S3 One Zone-IA after 90 days, then to S3 Glacier Flexible Retrieval after 2 years, and to S3 Glacier Deep Archive after 3 years.

Question 3

A company runs a three-tier application in a single AWS Region. The database tier is Amazon RDS for PostgreSQL with a Multi-AZ deployment, and the application reads from the primary endpoint. The company wants to reduce database cost while keeping high availability and read performance for a read-heavy workload. Which change should the company make?

Accepted Answer

Keep the Multi-AZ deployment and add a Multi-AZ DB cluster read replica, directing read-only queries to the reader endpoint.. An RDS Multi-AZ DB cluster deploys a writer and two readable standbys with a reader endpoint, so read-only queries are served by the standbys while the writer handles writes. This preserves high availability and improves read performance without provisioning separate read replica instances, which keeps cost lower than adding replicas and satisfies the read-heavy requirement.

Answer

Replace the Multi-AZ deployment with a Single-AZ deployment and enable automated backups.

Answer

Convert the database to Amazon Aurora PostgreSQL and add Aurora Replicas for read scaling.

Answer

Add RDS read replicas in the same Region and direct read traffic to the replica endpoint.

Question 4

A software company runs a CI/CD pipeline that builds container images in AWS CodeBuild and stores them in Amazon ECR. Build jobs run several times per hour, and the images are pulled by Amazon ECS tasks in the same Region. The company notices that data transfer charges and build times have increased. The pipeline and ECS cluster are in the same AWS account and Region. Which action will reduce cost and improve build performance MOST effectively?

Accepted Answer

Configure a VPC endpoint for Amazon ECR and for Amazon S3 so CodeBuild and ECS traffic stays on the AWS network.. Routing ECR and S3 traffic through VPC endpoints keeps image pulls on the AWS private network, eliminating NAT gateway data processing charges and improving throughput. Because CodeBuild and ECS operate in the same Region and account, this is the most direct way to cut transfer cost and speed up builds without changing the pipeline architecture.

Answer

Switch the ECR repository to use immutable image tags to prevent overwrites.

Answer

Enable ECR cross-Region replication to a second Region for redundancy.

Answer

Increase the CodeBuild compute type to a larger instance to speed up the build.

Question 5

A company runs a containerized microservices application on Amazon ECS. The workload is steady during business hours and drops sharply at night and on weekends. The team currently runs the tasks on EC2 instances in a cluster that is sized for peak load, so half the capacity sits idle much of the time. The team wants to reduce cost without rewriting the application and still needs control over instance types. Which approach should the solutions architect recommend?

Accepted Answer

Migrate the tasks to AWS Fargate and let ECS scale task count with demand.. AWS Fargate bills per task vCPU and memory per second, so cost tracks actual demand and idle capacity is never billed. Because the workload ebbs at night and on weekends, scaling task count under Fargate removes the peak-sized overprovisioning directly, without rewriting the application, which the EC2-based options cannot achieve as cleanly.

Answer

Run the tasks on Spot Instances in the ECS cluster with a capacity-optimized strategy.

Answer

Enable ECS cluster auto scaling with a target tracking policy on the EC2 Auto Scaling group.

Answer

Keep the EC2 cluster and purchase 3-year Reserved Instances for all peak capacity.

Question 6

A solutions architect is reviewing an application that stores millions of small JSON objects in an S3 bucket. The application writes each object once, reads it frequently for two weeks to serve an API, and then never reads it again, although the objects must be retained for three years for audit purposes. The team has noticed that the S3 bill is dominated by request charges rather than by stored bytes. Which two changes should the architect recommend to reduce cost? (Choose two.)

Accepted Answer

Aggregate the small JSON objects into larger objects before uploading them. The bill is driven by the sheer number of requests, so the highest-value change is to reduce request count by consolidating many small objects into fewer large ones. Once the two-week read window closes, a lifecycle transition to a cheaper archival class removes the residual storage cost for the remaining years, and neither change interferes with the audit retention requirement.

Answer

Switch the bucket to S3 Intelligent-Tiering with automatic archive access tiers enabled

Answer

Enable S3 Versioning on the bucket to protect against accidental deletion

Answer

Enable S3 Transfer Acceleration on the bucket to speed up uploads

Question 7

A company runs a containerized web application on Amazon ECS with the Fargate launch type. The application experiences highly variable traffic, with long periods of low usage and occasional spikes. The company wants to minimize costs while maintaining responsiveness during spikes. Which two actions should be taken? (Choose two.)

Accepted Answer

Configure a target tracking scaling policy based on CPU utilization with a target of 70%.. For variable traffic, cost optimization requires automatically scaling the number of tasks to match demand. Target tracking and step scaling policies both achieve this by responding to CloudWatch metrics, scaling out during spikes and scaling in during low usage. Scheduled scaling and fixed large task sizes do not adapt to unpredictable spikes, and switching to EC2 launch type adds management overhead without guaranteeing lower cost.

Answer

Use a scheduled scaling policy to increase task count every weekday at 08:00 and decrease it at 18:00.

Answer

Set the Fargate task size to the largest available CPU and memory configuration.

Answer

Run the application on EC2 instances with the EC2 launch type instead of Fargate to reduce cost.

Question 8

A company runs a three-tier web application on AWS. The application tier consists of six Amazon EC2 instances behind an Application Load Balancer, and the database tier uses Amazon RDS for MySQL with a Multi-AZ deployment. The EC2 instances run 24/7, and the company has committed to this workload for at least the next three years with no expected changes to instance families or Regions. A solutions architect needs to reduce compute costs without affecting availability. Which solution meets these requirements MOST cost-effectively?

Accepted Answer

Purchase a three-year Regional Standard Reserved Instance for each EC2 instance, and enable size flexibility within the same instance family.. The workload is steady for at least three years with no expected changes, which favors the highest-discount commitment model: a three-year Standard Reserved Instance. Regional scope applies the discount across all Availability Zones, so Multi-AZ failover or instance replacement does not break the benefit. Size flexibility within the instance family adds protection against right-sizing changes without sacrificing the Standard RI discount rate.

Answer

Purchase a three-year Compute Savings Plan and rely on it to cover the EC2 instances and the RDS database instance.

Answer

Purchase a three-year Standard Reserved Instance for each EC2 instance, scoped to the specific Availability Zone where each instance runs.

Answer

Purchase a three-year Convertible Reserved Instance for each EC2 instance and exchange them whenever a new instance family becomes available.

Question 9

A company stores application logs in an Amazon S3 bucket using the S3 Standard storage class. The logs are written once, never modified, and are accessed frequently for the first 30 days for troubleshooting. After 30 days, the logs are accessed only during quarterly audits. Regulatory requirements mandate that the logs be retained for seven years and that they remain retrievable within minutes if an audit occurs. A solutions architect must minimize storage costs while meeting the retrieval requirement. Which solution is MOST cost-effective?

Accepted Answer

Create an S3 Lifecycle configuration that transitions objects to S3 Glacier Instant Retrieval after 30 days and expires them after 2,555 days.. The requirement combines long retention with rapid retrieval. S3 Glacier Instant Retrieval is designed for exactly this pattern: it delivers millisecond access while costing less than S3 Standard-IA for data stored longer than 90 days. A lifecycle rule transitioning objects after 30 days and expiring them after seven years automates the cost reduction and satisfies the regulatory retention period.

Answer

Create an S3 Lifecycle configuration that transitions objects to S3 One Zone-IA after 30 days and expires them after 2,555 days.

Answer

Create an S3 Lifecycle configuration that transitions objects to S3 Standard-Infrequent Access after 30 days and expires them after 2,555 days.

Answer

Create an S3 Lifecycle configuration that transitions objects to S3 Glacier Deep Archive after 30 days and expires them after 2,555 days.

Question 10

A solutions architect is designing storage for a new application that writes 40 TB of data per month. The data is accessed frequently for the first 30 days, occasionally for the next 60 days, and is then retained for compliance for one year with almost no access. The team wants the lowest storage cost while keeping retrieval immediate for the first 90 days. Which S3 configuration should the architect recommend?

Accepted Answer

An S3 Lifecycle policy that transitions objects from S3 Standard to S3 Standard-IA after 30 days, then to S3 Glacier Instant Retrieval after 90 days, and expires them after 365 days.. The access curve has three phases, and the storage class should follow it. S3 Standard absorbs the heavy first month, S3 Standard-IA handles the occasional-access window at a lower per-gigabyte price, and S3 Glacier Instant Retrieval covers the long compliance tail where access is rare but must remain millisecond-latency. A 365-day expiration enforces the retention rule and stops charges after the obligation ends.

Answer

An S3 Lifecycle policy that transitions objects to S3 One Zone-IA after 30 days and to S3 Glacier Flexible Retrieval after 90 days.

Answer

Keep all objects in S3 Standard for the full year and enable S3 Intelligent-Tiering.

Answer

An S3 Lifecycle policy that transitions objects directly from S3 Standard to S3 Glacier Deep Archive after 30 days.

Question 11

A company runs a stateful web application on multiple Amazon EC2 instances in a single Availability Zone. The instances store session data on their local instance store volumes and use a shared Amazon EBS volume for application data. The company wants to reduce costs by using Spot Instances for the web tier, but is concerned about data loss when instances are interrupted. What should a solutions architect recommend to meet the cost goal while minimizing data loss?

Accepted Answer

Use Spot Instances with a persistent request and configure the application to store session data on the shared Amazon EBS volume.. Spot Instances reduce compute costs by using spare EC2 capacity, but they can be interrupted with a short warning. To avoid data loss, state must be externalized from instance store to a durable, shared storage layer such as Amazon EBS. A persistent Spot request automatically requests replacement instances to maintain capacity, aligning with the cost and availability goals. This combination balances savings with resilience.

Answer

Use Spot Instances and configure the application to write session data to an Amazon S3 bucket after each request.

Answer

Use Spot Instances with a one-time request and enable termination protection on each instance.

Answer

Use On-Demand Instances for the web tier and purchase a Compute Savings Plan to reduce costs.

Question 12

A company runs a large-scale data analytics application on Amazon EC2 instances that process data stored in Amazon S3. The application reads the same 500 GB dataset repeatedly each day, and the instances are launched in an Auto Scaling group. The company wants to reduce both compute and data transfer costs. What should a solutions architect recommend?

Accepted Answer

Use an Amazon S3 gateway endpoint and mount the S3 bucket as a file system using AWS Storage Gateway File Gateway.. The combination of an S3 gateway endpoint and AWS Storage Gateway File Gateway reduces costs by avoiding NAT gateway data processing fees and caching frequently accessed data locally. The File Gateway presents S3 objects as files over NFS/SMB, so the analytics application can read the dataset from the cache without repeatedly retrieving it from S3. This minimizes data transfer and improves performance, which indirectly reduces compute time and cost.

Answer

Store the dataset in an Amazon EBS volume and attach it to each instance.

Answer

Use an Amazon S3 gateway endpoint and cache the dataset on instance store volumes.

Answer

Use an Amazon S3 gateway endpoint and enable S3 Transfer Acceleration.

Question 13

A company is designing a cost-optimized architecture for a new application on AWS. The application will use Amazon S3 for storage, Amazon RDS for a relational database, and Amazon EC2 for compute. The company wants to minimize costs while ensuring high availability. Which two actions should they take? (Choose two.)

Accepted Answer

Implement S3 Lifecycle policies to transition objects to lower-cost storage classes.. Using RDS Reserved Instances and implementing S3 Lifecycle policies are both effective cost-optimization strategies for their respective services. RDS Reserved Instances reduce database costs for steady-state workloads, while S3 Lifecycle policies automatically move data to lower-cost storage classes as access patterns change. These actions maintain high availability and do not compromise performance.

Answer

Deploy EC2 instances in a single Availability Zone to reduce data transfer costs.

Answer

Use EC2 Spot Instances for the compute layer.

Answer

Enable S3 Intelligent-Tiering to automatically move data between access tiers.

Question 14

A company runs a microservices architecture on Amazon ECS with Fargate. The services communicate over a service mesh and generate a large volume of logs. The logs are stored in Amazon CloudWatch Logs. The company wants to reduce logging costs while maintaining the ability to troubleshoot recent issues. Logs older than 30 days are rarely accessed but must be retained for 1 year for audit purposes. Which solution is MOST cost-effective?

Accepted Answer

Use CloudWatch Logs subscription filters to stream logs to Amazon S3 in near real-time, and set CloudWatch Logs retention to 30 days.. Using CloudWatch Logs subscription filters to stream logs to Amazon S3 in near real-time, combined with a 30-day retention in CloudWatch Logs, balances cost and accessibility. S3 provides durable, low-cost storage for long-term retention, and CloudWatch Logs retains recent logs for immediate troubleshooting. This solution minimizes costs without sacrificing audit or operational needs.

Answer

Disable logging for all services to eliminate CloudWatch Logs costs.

Answer

Increase the CloudWatch Logs retention period to 1 year and use CloudWatch Logs Insights for querying.

Answer

Configure CloudWatch Logs to export logs to Amazon S3 after 30 days and set retention to 1 year.

Question 15

A company runs a nightly batch analytics pipeline on AWS Fargate tasks that process 400 GB of intermediate data. The pipeline writes intermediate results to Amazon S3 and later reads them back several times within the same 48-hour run. The engineering team wants to minimize storage costs for these intermediate files and does not need them after the pipeline completes each week. Which solution is the MOST cost-effective?

Accepted Answer

Store intermediate objects in S3 Standard and add a lifecycle rule to expire them 7 days after creation.. Short-lived intermediate data that is read repeatedly within the same run is best kept in S3 Standard, which has no retrieval fees and no minimum storage duration. The lifecycle expiration rule removes the objects after the job window, so charges stop automatically. Colder classes impose minimum-duration charges and retrieval fees that exceed any savings for data living only days.

Answer

Configure an S3 Lifecycle rule to transition intermediate objects to S3 Glacier Instant Retrieval after 30 days and expire them after 90 days.

Answer

Store intermediate objects in S3 One Zone-IA and add a lifecycle rule to expire them after 7 days.

Answer

Store intermediate objects in S3 Intelligent-Tiering and rely on its automatic tiering to move objects to the Archive Access tier.