SAA-C03 Design Cost-Optimized Architectures Practice Test 4 — 15 Questions

Question 1

A team runs an Amazon NLB in a VPC with targets registered in multiple Availability Zones (AZs). Their bill shows high inter-AZ data transfer charges. They want to reduce unnecessary cross-AZ traffic costs while still maintaining healthy targets per AZ. What change is most likely to reduce inter-AZ charges?

Accepted Answer

Disable cross-zone load balancing on the NLB so each client is routed to targets in the same AZ when possible.. Option A is correct because disabling cross-zone load balancing on an NLB ensures that each client is routed only to targets within the same Availability Zone as the NLB node that receives the traffic. This eliminates inter-AZ data transfer charges because traffic never leaves the AZ boundary, while still maintaining healthy targets per AZ as each AZ independently handles its own client requests.

Answer

Enable cross-zone load balancing so all targets receive traffic from every AZ.

Answer

Move the NLB to a different Region so traffic is always kept local.

Answer

Replace the NLB with a NAT gateway to reduce data charges between AZs.

Question 2

A company keeps daily database backups in an S3 bucket. They may restore from backups during the first 30 days if there is an issue. After 30 days, backups are rarely restored, but must be retained for 2 years. Which lifecycle strategy most cost-effectively meets these requirements?

Accepted Answer

Use an S3 lifecycle policy to keep backups in S3 Standard for 30 days, then transition them to S3 Glacier Deep Archive for the remainder of the 2-year retention period.. Option C is correct because it uses an S3 lifecycle policy to store backups in S3 Standard for the first 30 days when restores are likely, then transitions them to S3 Glacier Deep Archive for the remaining retention period. S3 Glacier Deep Archive offers the lowest storage cost for long-term, rarely accessed data, making this the most cost-effective strategy while meeting the 2-year retention requirement.

Answer

Delete backups after 30 days to avoid storage costs, since restores are rare.

Answer

Keep all backups in S3 Standard for the entire 2-year retention period.

Answer

Move backups to S3 Glacier Deep Archive immediately after creation, even for the first 30 days.

Question 3

A startup has a stable production web service that runs continuously (24/7) on AWS. They have consistent compute requirements for the next 1 year, but the instance size and family might change as they optimize performance. To reduce cost while maintaining flexibility across instance types, which purchasing option should they consider?

Accepted Answer

Compute Savings Plans. Compute Savings Plans offer the lowest prices for EC2 compute usage (up to 66% off On-Demand) while allowing flexibility to change instance family, size, OS, and region (within a region). This matches the startup's need for consistent 1-year compute requirements with potential instance type changes during performance optimization.

Answer

Reserved Instances with a fixed instance type

Answer

Spot Instances

Answer

On-Demand Instances

Question 4

A company stores compliance reports in Amazon S3. Objects are written once and rarely accessed. They need to keep the data for 3 years. When retrieval is needed for an audit, the reports can be restored within hours (not minutes). What storage class should the company use for new objects, assuming minimal operational overhead?

Accepted Answer

S3 Glacier Flexible Retrieval. S3 Glacier Flexible Retrieval is the correct choice because it offers retrieval times of minutes to hours (typically 1–5 minutes for expedited, 3–5 hours for standard), which aligns with the 'within hours' requirement. It is designed for data that is rarely accessed but must be retained for long periods (3 years), and it provides a low-cost storage class with minimal operational overhead since objects can be transitioned via lifecycle policies or stored directly.

Answer

S3 Standard

Answer

S3 Intelligent-Tiering

Answer

S3 Glacier Deep Archive

Question 5

An application runs on EC2 in us-east-1 and frequently reads objects from an S3 bucket that is physically located in us-west-2. The finance team reports unexpectedly high inter-Region data transfer charges because the application retrieves objects for many user requests. A constraint: the bucket in us-west-2 must remain the system of record for compliance, but the application can read from a replica in us-east-1.

What should the solutions architect do to minimize network spend while meeting the compliance constraint?

Accepted Answer

Enable S3 Cross-Region Replication from the us-west-2 source bucket to a destination bucket in us-east-1, and update the app to read from the us-east-1 bucket.. Option A is correct because enabling S3 Cross-Region Replication (CRR) automatically copies objects from the us-west-2 source bucket to a destination bucket in us-east-1, satisfying the compliance requirement that the us-west-2 bucket remains the system of record. By updating the application to read from the us-east-1 replica, all data retrieval traffic stays within the same region, eliminating inter-Region data transfer charges (which are typically $0.02/GB for S3 GET requests across regions). This approach directly addresses the cost issue while preserving the original bucket as the authoritative source.

Answer

Create an interface VPC endpoint for S3 in us-east-1 and keep all object reads pointing to the us-west-2 bucket.

Answer

Use VPC peering between two regions and route all requests to the us-west-2 bucket over the peering link.

Answer

Use Route 53 latency-based routing to send users to a us-west-2 web endpoint and keep the S3 bucket unchanged.

Question 6

A SaaS company uses an S3 bucket for database backups created daily. Backups are rarely restored; the company’s documented RTO is 24 hours, and the compliance policy requires backups be kept for 90 days. The team currently stores all backups in S3 Standard, which is costly.

Which single lifecycle policy change is most cost-optimized while still meeting the 24-hour RTO and 90-day retention?

Accepted Answer

Add a lifecycle rule to transition backups older than 1 day to S3 Glacier Flexible Retrieval, and keep them until day 90.. Option A is correct because S3 Glacier Flexible Retrieval provides retrieval times from minutes to hours, which meets the 24-hour RTO, and offers significant cost savings over S3 Standard for data that is rarely accessed. Transitioning backups older than 1 day to this storage class reduces costs while retaining them for the required 90-day compliance period.

Answer

Add a lifecycle rule to transition backups older than 1 day to S3 Glacier Instant Retrieval, and keep them until day 90.

Answer

Add a lifecycle rule to transition backups older than 1 day to S3 Glacier Deep Archive, and keep them until day 90 with no restore configuration.

Answer

Add a lifecycle rule to transition backups older than 1 day to S3 One Zone-IA, and delete them after 7 days.

Question 7

A data engineering team runs a nightly ETL job on EC2. The job can be checkpointed every 5 minutes and can be retried from the last checkpoint if the instance terminates. The job runtime varies from 2 to 4 hours, and the team has no need for a specific instance type, as long as it completes before 7:00 AM local time. They currently run the job on On-Demand EC2, leading to high monthly compute cost.

Which change best reduces cost while maintaining the business deadline?

Accepted Answer

Use Spot Instances for the ETL workload, and configure the job to checkpoint frequently and restart on interruption.. Option A is correct because Spot Instances offer significant cost savings (up to 90% compared to On-Demand) and are ideal for fault-tolerant, checkpointable workloads. The job's ability to checkpoint every 5 minutes and retry from the last checkpoint means it can gracefully handle Spot Instance interruptions, ensuring it still completes before the 7:00 AM deadline without incurring the high cost of On-Demand instances.

Answer

Use Reserved Instances with a 1-year term to lower costs, since reservations provide discounts for any usage.

Answer

Switch to On-Demand but enable Auto Scaling so the job finishes faster during peak hours.

Answer

Use Spot Instances but disable checkpointing to simplify the application.

Question 8

A company stores application logs in an S3 bucket. They retain logs for 180 days. Compliance requires that the logs be immutable once written, but the business only reviews logs about once per month. Currently, the team stores everything in S3 Standard, and their monthly S3 bill is too high. They want to reduce storage cost without changing the requirement to keep logs for 180 days.

Which lifecycle approach best meets the goal?

Accepted Answer

Use a lifecycle policy to transition objects older than 30 days to S3 Standard-IA, and keep them there until day 180.. Option A is correct because it transitions logs to S3 Standard-IA after 30 days, which reduces storage costs while still meeting the 180-day retention requirement. S3 Standard-IA is designed for data accessed less frequently but requires rapid access when needed, aligning with the monthly review pattern. The lifecycle policy keeps objects in S3 Standard-IA until day 180, ensuring immutability (via S3 Object Lock or bucket policies) and compliance without premature deletion.

Answer

Use a lifecycle policy to transition objects older than 30 days to S3 Glacier Deep Archive and delete after 30 days.

Answer

Use a lifecycle policy to transition objects older than 30 days to S3 Intelligent-Tiering with no minimum storage duration.

Answer

Disable lifecycle management and instead lower costs by deleting objects immediately after they are written.

Question 9

A media company runs a 24/7 recommendation engine on EC2 in one AWS Region. The workload is interruption-intolerant, and the team expects steady usage but may change instance families and sizes during planned optimizations. Compared to the current On-Demand setup, they want the lowest cost while avoiding the rigidity of locking to a specific instance type.

What should the solutions architect recommend?

Accepted Answer

Purchase a Compute Savings Plan for the expected steady hourly usage in that Region.. A Compute Savings Plan offers the lowest cost for steady-state usage without locking to a specific instance type, providing up to 66% discount over On-Demand while allowing flexibility to change instance families, sizes, OS, or tenancy within a Region. This matches the requirement for cost savings with instance flexibility during planned optimizations.

Answer

Switch the instances to Spot Instances and use interruption handling because it is the largest discount.

Answer

Purchase a Standard Reserved Instance tied to a single specific instance type for the next 3 years.

Answer

Keep On-Demand and rely on Auto Scaling to reduce capacity when utilization is low.

Question 10

A media company runs a batch job that processes image thumbnails. The job can be restarted from checkpoints and does not have user-facing SLAs. The batch capacity can tolerate interruptions. Which EC2 purchasing option is the best cost optimization choice?

Accepted Answer

Use EC2 Spot Instances, accepting the possibility of interruptions and using checkpoints to resume.. Spot Instances offer significant cost savings (up to 90% compared to On-Demand) and are ideal for fault-tolerant, stateless, or checkpointable workloads like batch image thumbnail processing. Since the job can resume from checkpoints and tolerates interruptions, Spot Instances provide the best cost optimization without compromising functionality.

Answer

Use On-Demand Instances because interruptions are not allowed for production workloads.

Answer

Purchase Reserved Instances because they provide a discount regardless of the workload timing.

Answer

Buy Savings Plans because they guarantee capacity and remove the risk of interruptions entirely.

Question 11

An internal team runs a report-generation job once per day. It typically finishes in a few minutes, and even on its slowest days it still completes in under 15 minutes. The team wants to reduce operational overhead and pay primarily for actual runtime instead of keeping servers running 24/7. Which AWS approach best matches these goals?

Accepted Answer

Use AWS Lambda triggered by a schedule (for example, EventBridge) to run the report at the required time.. AWS Lambda is the ideal choice because it is a serverless compute service that runs code only when triggered, aligning with the requirement to pay primarily for actual runtime. By using Amazon EventBridge (CloudWatch Events) to invoke the Lambda function on a daily schedule, the team eliminates the need to provision or manage servers, and the job's typical runtime of a few minutes (under 15 minutes, Lambda's maximum execution timeout) fits perfectly within Lambda's constraints.

Answer

Deploy the job on EC2 instances and keep them running continuously for the daily schedule.

Answer

Run the job in an RDS database using stored procedures scheduled by the database engine.

Answer

Use an Auto Scaling group with a fixed minimum size of one instance and disable scaling.

Question 12

A company processes product-image uploads in bursts. Each transform takes up to ten minutes, and every job can be retried safely from the beginning. The current EC2 worker fleet is idle most of the day. Which two changes most reduce cost and idle capacity? Select two.

Accepted Answer

Buffer jobs in Amazon SQS and let workers scale from queue depth.. Option A is correct because Amazon SQS can decouple the upload bursts from the worker fleet, allowing the workers to scale based on the ApproximateNumberOfMessagesVisible metric via a target tracking scaling policy. This eliminates idle capacity by keeping workers at zero when no jobs are queued and scaling up only when bursts arrive. Option B is correct because AWS Fargate Spot provides up to a 70% discount over On-Demand, and since each transform can be retried safely from the beginning, interruptions are acceptable without data loss.

Answer

Keep a fixed fleet of m6i.large instances in an Auto Scaling group with a higher minimum.

Answer

Use Reserved Instances for the workers even though demand is highly bursty.

Answer

Process uploads only during a nightly window so the fleet looks busier.

Question 13

A photo studio stores original project archives in Amazon S3. Objects are read heavily for 14 days after upload, occasionally during the next 11 months, and almost never after one year. The team wants the lowest storage cost while keeping retrieval within minutes during the first year. Which three actions are best? Select three.

Accepted Answer

Keep new objects in S3 Standard for the first 14 days.. A is correct because S3 Standard is designed for frequently accessed data with low latency and high throughput, making it ideal for the first 14 days when objects are read heavily. This storage class provides immediate retrieval and no retrieval costs, aligning with the requirement for minutes-level access during the first year.

Answer

Transition objects to S3 Glacier Flexible Retrieval after 14 days.

Answer

Disable versioning to make the lifecycle rules work correctly.

Question 14

A SaaS vendor has a steady 24/7 control plane on ECS and several small event-driven tasks that currently run on a separate always-on service. Management wants the billing discount that applies across both ECS and Lambda usage without committing to a specific instance family. Which two actions are best? Select two.

Accepted Answer

Buy a Compute Savings Plan for the predictable baseline usage.. A Compute Savings Plan offers the largest discount (up to 66%) across both ECS and Lambda usage without committing to a specific instance family, which matches the requirement for a flexible discount. It applies to any EC2 instance, including those used by ECS, and also covers AWS Lambda compute usage, making it ideal for mixed workloads with predictable baseline usage.

Answer

Buy an EC2 Instance Savings Plan tied to one instance family for all workloads.

Answer

Use Spot Instances for the control plane because it is the largest bill.

Answer

Increase the ECS desired count so Lambda can be removed.

Question 15

Multiple teams share one AWS Organization. Finance wants chargeback by project, alerts before overspend, and monthly views by account without manually opening each account. Which three actions best fit? Select three.

Accepted Answer

Enforce cost allocation tags on resources and activate them for billing reports.. Option A is correct because cost allocation tags allow you to tag resources with project-specific metadata (e.g., 'Project: Alpha'), and activating them for billing reports ensures that AWS Cost Explorer and Cost and Usage Reports can group and filter costs by those tags. This directly enables chargeback by project without manual account inspection, as the tags are propagated into the billing data.

Answer

Put every team in a separate AWS account and ignore tagging.

Answer

Use CloudTrail trails to estimate spend by resource because it records API calls.