SOA-C02 Cost and Performance Optimization Practice Test 9 — 15 Questions

Question 1

A company runs a critical web application on EC2 instances behind an ALB. The application experiences unpredictable traffic spikes. The SysOps administrator wants to ensure that the application can handle spikes without performance degradation while minimizing costs. Which TWO actions should the administrator take?

Accepted Answer

Use a mix of On-Demand and Spot Instances in the Auto Scaling group.. Option A is correct because Spot Instances can reduce costs if the application can handle interruptions. Option D is correct because target tracking scaling adjusts capacity based on load. Option B is wrong because DynamoDB auto scaling is not relevant for EC2. Option C is wrong because scheduled scaling cannot handle unpredictable spikes. Option E is wrong because increasing instance size may not be as cost-effective as scaling out.

Answer

Use Amazon DynamoDB auto scaling to handle the spikes.

Answer

Use scheduled scaling to add instances during expected peak hours.

Answer

Use larger EC2 instance types to handle spikes.

Question 2

A company is using Amazon S3 to store data for analytics. The data is accessed frequently for the first 30 days, then rarely after that. The company wants to optimize storage costs. Which THREE actions should the SysOps administrator recommend?

Accepted Answer

Use S3 Intelligent-Tiering to automatically optimize storage costs.. Option B is correct because S3 Intelligent-Tiering automatically moves data between tiers. Option C is correct because lifecycle policies can transition objects to colder storage. Option E is correct because S3 Glacier Deep Archive is the cheapest for long-term archival. Option A is wrong because S3 Standard is more expensive than Standard-IA for infrequent access. Option D is wrong because S3 One Zone-IA is for infrequent access but does not provide high availability.

Answer

Use S3 One Zone-IA for all data after 30 days to reduce costs.

Answer

Use S3 Standard storage for all data to ensure high performance.

Question 3

A company is using Amazon CloudFront to deliver content to users worldwide. They notice high data transfer costs. Which THREE actions can reduce CloudFront data transfer costs?

Accepted Answer

Use a CloudFront price class that only uses the cheapest edge locations.. Option A is correct because price class selects only the cheapest edge locations. Option B is correct because compressing objects reduces transfer size. Option D is correct because origin shield reduces requests to the origin. Option C is wrong because Lambda@Edge adds cost. Option E is wrong because more edge locations increase coverage but not necessarily reduce cost.

Answer

Use Lambda@Edge to customize content.

Answer

Add more edge locations to improve cache hit ratio.

Question 4

A company runs a web application on EC2 instances in an Auto Scaling group behind an ALB. The application experiences variable traffic, with peak usage during business hours and low traffic at night. The SysOps administrator wants to reduce costs while maintaining performance. The current setup uses On-Demand instances only. The application is stateful and stores session data in an ElastiCache Redis cluster. The administrator has identified that the application can handle Spot Instance interruptions gracefully by redirecting users to a fallback page. The company has a budget of $10,000 per month for EC2 instances, and current costs are $8,000 per month. The administrator wants to reduce costs further without compromising availability for most users. Which solution is MOST cost-effective?

Accepted Answer

Use a mixed instances policy with Spot Instances during off-peak hours and On-Demand during peak hours, using Auto Scaling scheduled scaling.. Option C is correct because using Spot Instances only during off-peak hours reduces costs, and moving back to On-Demand during peak ensures performance. Option A is wrong because Spot Instances only during peak could cause interruptions during high traffic. Option B is wrong because Reserved Instances require commitment and may not cover variable traffic. Option D is wrong because a larger base On-Demand capacity increases costs.

Answer

Increase the On-Demand base capacity to handle peak load and use Spot for any additional capacity.

Answer

Purchase Reserved Instances for the minimum expected capacity and use On-Demand for the rest.

Answer

Use only Spot Instances at all times to maximize savings, and rely on the fallback page for interruptions.

Question 5

A company runs a data processing pipeline on AWS. The pipeline consists of EC2 instances that process data from an S3 bucket and write results to another S3 bucket. The processing job runs every hour and takes approximately 45 minutes. The current setup uses On-Demand instances. The SysOps administrator wants to reduce costs because the monthly EC2 bill is $5,000. The application is fault-tolerant and can handle interruptions by reprocessing data from the last checkpoint. The administrator has tested Spot Instances and found that they are interrupted about 10% of the time. The company has a strict requirement that the job must complete within 60 minutes every hour. Which solution would reduce costs while ensuring the job completes on time?

Accepted Answer

Use a Spot Fleet with a fallback to On-Demand if Spot capacity is not available.. Option D is correct because a Spot Fleet with a fallback to On-Demand ensures the job completes even if Spot Instances are interrupted. Option A is wrong because Spot Instances only may not complete within the time if interrupted. Option B is wrong because Reserved Instances require commitment and may not be needed for the full hour. Option C is wrong because a larger instance increases costs.

Answer

Purchase Reserved Instances for the expected capacity to get a discount.

Answer

Use a single larger On-Demand instance to complete the job faster.

Answer

Use Spot Instances only and increase the number of instances to compensate for interruptions.

Question 6

A company is running a production web application on EC2 instances behind an Application Load Balancer. The company wants to optimize costs without sacrificing performance. Which TWO actions should the SysOps administrator take?

Accepted Answer

Purchase Reserved Instances for the baseline capacity.. Option A (Reserved Instances) provides a significant discount for steady-state workloads, and Option C (Auto Scaling) ensures capacity matches demand, preventing over-provisioning. Option B (Dedicated Hosts) is more expensive and unnecessary. Option D (T3 unlimited) could cause unexpected costs if credits exhausted. Option E (Multiple instance types per AZ) is not a cost optimization.

Answer

Use Dedicated Hosts for all instances to control placement.

Answer

Enable T2/T3 unlimited to handle spikes without throttling.

Answer

Use multiple instance types in each Availability Zone.

Question 7

A SysOps administrator manages a fleet of 50 EC2 instances running a batch processing application. The instances are launched via an Auto Scaling group with a dynamic scaling policy based on CPU utilization. The company recently switched to a new workload that is memory-intensive, causing frequent scale-out events. The administrator notices that the CPU utilization remains below 40%, but memory usage is consistently above 80%. The scaling policy does not trigger appropriately, leading to performance degradation. The administrator must optimize the solution to respond to memory pressure without incurring unnecessary costs. Which action should the administrator take?

Accepted Answer

Create a custom CloudWatch metric for memory utilization and configure a target tracking scaling policy using that metric.. Option C is correct because creating a custom CloudWatch metric for memory utilization and using a target tracking policy allows Auto Scaling to respond to the actual bottleneck. Option A (changing to step scaling with CPU) does not address memory. Option B (manual scaling) is not automated. Option D (t3.large) is a reactive instance type change, not a scaling solution.

Answer

Increase the minimum size of the Auto Scaling group to 10 instances and use manual scaling for peak times.

Answer

Change the dynamic scaling policy to a step scaling policy based on CPU utilization with a wider cooldown period.

Answer

Replace the current instance type with a memory-optimized instance type such as r5.large.

Question 8

A company runs a fleet of EC2 instances in a production environment. The instances are part of an Auto Scaling group that uses a launch template with a m5.large instance type. The company's SysOps administrator notices that the instances are often over-provisioned, with average CPU utilization below 20% for the past month. The administrator wants to reduce costs without affecting application performance. The application is stateless and can handle temporary performance degradation. Which action should the administrator take?

Accepted Answer

Modify the launch template to use a t3.medium instance type.. Option B is correct because switching to a smaller instance type (t3.medium) reduces cost while still providing burstable performance for occasional spikes. Option A (increase minimum) would increase cost. Option C (purchase Reserved Instances for current size) locks in over-provisioned capacity. Option D (enable detailed monitoring) increases CloudWatch costs without addressing instance size.

Answer

Purchase Reserved Instances for the current m5.large instances to lower hourly cost.

Answer

Enable detailed monitoring on all instances to collect more data.

Answer

Increase the minimum size of the Auto Scaling group to reduce scale-out events.

Question 9

A SysOps administrator is responsible for an AWS account that hosts a development environment. The environment includes several EC2 instances that are used only during business hours (9 AM to 5 PM) on weekdays. The administrator wants to reduce costs by stopping the instances during off-hours. Which action should the administrator take to automate this process?

Accepted Answer

Use the AWS Instance Scheduler to define a schedule that stops instances at 5 PM and starts them at 9 AM on weekdays.. Option A is correct because AWS Instance Scheduler is a solution that automatically starts and stops instances based on a schedule. Option B (manual stop) is not automated. Option C (Auto Scaling) does not stop instances, it adds/removes based on demand. Option D (CloudWatch alarm) can stop instances based on CPU, but not a fixed schedule.

Answer

Manually stop the instances at 5 PM and start them at 9 AM each weekday.

Answer

Create an Auto Scaling group with a scheduled scaling action to set desired capacity to 0 during off-hours.

Answer

Set up a CloudWatch alarm that stops instances when CPU utilization is below 1% for 30 minutes.

Question 10

A company runs a web application on EC2 instances behind an Application Load Balancer (ALB). The application experiences variable traffic with occasional spikes. The SysOps administrator wants to optimize costs while ensuring that the application can handle spikes without performance degradation. The current setup uses a fixed number of instances. Which action should the administrator take?

Accepted Answer

Implement an Auto Scaling group with a target tracking scaling policy based on ALB request count per target.. Option C is correct because Auto Scaling with a target tracking policy on ALB request count allows the number of instances to adjust based on traffic, handling spikes and reducing instances during low traffic. Option A (increase instance size) may handle spikes but is expensive for low traffic. Option B (Reserved Instances) locks in a fixed capacity. Option D (Spot Instances) are cheaper but can be interrupted, risking performance degradation during spikes.

Answer

Purchase Reserved Instances for the current number of instances to reduce hourly cost.

Answer

Replace on-demand instances with Spot Instances for all traffic.

Answer

Increase the instance size to a compute-optimized type to handle spikes.

Question 11

A company runs a web application on EC2 instances behind an Application Load Balancer. The application experiences variable traffic patterns. The operations team notices that during low traffic periods, there are still a large number of running instances, leading to higher costs. What should the team do to reduce costs while maintaining performance?

Accepted Answer

Implement a target tracking scaling policy based on average CPU utilization.. Using a target tracking scaling policy based on average CPU utilization allows the Auto Scaling group to automatically adjust the number of instances based on demand, reducing costs during low traffic. Option A is wrong because manual scaling does not automate cost optimization. Option B is wrong because Reserved Instances do not address variable traffic. Option D is wrong because increasing instance size may not reduce the number of instances during low traffic.

Answer

Replace the existing instances with larger instance types to handle peak load.

Answer

Manually scale down the number of instances during off-peak hours.

Answer

Purchase Reserved Instances for the baseline capacity.

Question 12

A company uses a centralized logging solution with Amazon OpenSearch Service. The log volume has grown significantly, increasing costs. The logs are retained for 90 days for compliance, but only the last 30 days are frequently accessed. Which combination of actions would reduce costs without compromising compliance?

Accepted Answer

Migrate indices older than 30 days to UltraWarm nodes.. Using UltraWarm nodes for older data reduces storage costs while retaining data for 90 days. Option A is wrong because deleting data after 30 days violates compliance. Option C is wrong because increasing instance count increases costs. Option D is wrong because cold storage retrieval is not appropriate for OpenSearch.

Answer

Move the logs to Amazon S3 Glacier and use a Lambda function to query them.

Answer

Increase the number of data nodes to improve indexing performance.

Answer

Configure an index lifecycle policy to delete indices older than 30 days.

Question 13

An application running on Amazon EC2 generates a large number of small files that are stored temporarily and deleted after 24 hours. The files are accessed frequently within the first hour and then rarely. Which Amazon S3 storage class is MOST cost-effective for this use case?

Accepted Answer

S3 Intelligent-Tiering. S3 Intelligent-Tiering automatically moves objects between tiers based on access patterns, making it cost-effective for unpredictable access. Option A is wrong because S3 Standard is more expensive for rarely accessed data. Option B is wrong because S3 One Zone-IA may have lower durability but not necessarily lower cost for this pattern. Option D is wrong because S3 Glacier Deep Archive has a minimum storage duration of 180 days.

Answer

S3 Glacier Deep Archive

Answer

S3 One Zone-Infrequent Access

Answer

S3 Standard

Question 14

A SysOps administrator notices that an Amazon RDS for MySQL instance has high read activity. The application performs many read queries but few writes. The database is currently a single db.r5.large instance. What change would improve read performance and reduce cost?

Accepted Answer

Create a read replica and use a smaller instance type for the replica.. Adding a read replica distributes read traffic, improving performance, and using a smaller instance type for the replica reduces cost. Option A is wrong because vertical scaling increases cost. Option B is wrong because Multi-AZ does not offload reads. Option D is wrong because moving to DynamoDB may not be compatible with the application.

Answer

Enable Multi-AZ for high availability and use the standby for reads.

Answer

Increase the instance size to db.r5.xlarge.

Answer

Migrate the database to Amazon DynamoDB.

Question 15

A company has a production AWS account that uses Consolidated Billing with several member accounts. The finance team wants to identify the top cost drivers and allocate costs to different departments. Which AWS tool should be used to visualize and allocate costs?

Accepted Answer

AWS Cost Explorer. AWS Cost Explorer provides visualization and filtering of costs by tags, accounts, and services, enabling cost allocation. Option A is wrong because Trusted Advisor provides optimization recommendations but not detailed cost allocation. Option C is wrong because Budgets only creates budget alerts. Option D is wrong because Organizations is for policy management.

Answer

AWS Organizations

Answer

AWS Trusted Advisor

Answer

AWS Budgets