SOA-C02 Cost and Performance Optimization Practice Test 11 — 15 Questions

Question 1

A company is using Amazon RDS for MySQL with Multi-AZ deployment. They want to optimize costs while maintaining high availability. Which TWO actions should the SysOps administrator take?

Accepted Answer

Purchase Reserved Instances for the database instance.. Option A is correct because purchasing Reserved Instances for the RDS DB instance provides a significant discount (up to ~69% for 3-year All Upfront terms) compared to On-Demand pricing, directly reducing cost while leaving the Multi-AZ high-availability configuration fully intact. Option D is correct because rightsizing the DB instance class (for example, moving from db.m5.xlarge to db.m5.large) eliminates spend on over-provisioned CPU/memory, and it can be done with a modification that preserves the Multi-AZ standby, so high availability is maintained. Option B is wrong because removing Multi-AZ sacrifices the synchronous standby replica and automatic failover, violating the requirement to maintain high availability. Option C is wrong because RDS does not support auto scaling of the DB instance itself; only storage can be auto scaled, and read scaling requires Read Replicas, not instance auto scaling. Option E is wrong because a Single-AZ deployment plus snapshots is not highly available—snapshot restore creates a new instance and involves substantial RPO/RTO, so it fails the availability requirement.

Answer

Remove Multi-AZ to reduce costs.

Answer

Enable auto scaling for the RDS instance to handle variable load.

Answer

Move to a single-AZ deployment and take snapshots for recovery.

Question 2

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.. 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 3

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.. The correct actions are A, C, D. Option A: S3 Intelligent-Tiering automatically moves data between tiers based on access patterns, optimizing costs for data with changing access patterns. Option C: A lifecycle policy to transition objects to S3 Glacier Deep Archive after 90 days is appropriate for data that is rarely accessed after the initial 30 days. Option D: A lifecycle policy to transition objects to S3 Standard-IA after 30 days is a good cost-saving measure for data that is accessed infrequently after the first 30 days. Option B is incorrect because S3 One Zone-IA is not durable enough for analytics data that may need availability, and it does not automatically optimize costs like Intelligent-Tiering. Option E is incorrect because using S3 Standard for all data would be more expensive than using the lifecycle policies or Intelligent-Tiering.

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 4

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.. (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 5

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.. It directly addresses the memory bottleneck by creating a custom CloudWatch metric for memory utilization and using a target tracking scaling policy. This allows the Auto Scaling group to automatically adjust capacity based on actual memory pressure, which is the real performance issue. Option B (manual scaling) is not automated and may lead to over-provisioning or under-provisioning. Option C (step scaling with CPU) does not solve the memory problem, and a wider cooldown would only delay scaling. Option D (changing instance type) is a reactive measure that does not provide dynamic scaling and may increase costs without eliminating the need for scaling policies.

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 6

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.. Modifying the launch template to use a t3.medium instance type is correct because t3 instances are burstable and cost-effective for workloads with low average CPU utilization (below 20%). The application is stateless and can handle temporary performance degradation, making burstable instances suitable. This reduces costs without affecting performance during normal operation, as t3.medium provides a baseline CPU with the ability to burst.

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 7

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.. AWS Instance Scheduler is a solution that automates the starting and stopping of EC2 instances based on a schedule. It uses Lambda functions and DynamoDB to manage schedules, and it can be configured to stop instances at 5 PM and start them at 9 AM on weekdays, reducing costs during off-hours.

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 8

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.. An Auto Scaling group with a target tracking policy based on ALB request count per target automatically scales instances in and out to match traffic, handling spikes while minimizing cost during low-traffic periods. This directly addresses variable traffic with occasional 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 9

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.. The problem is over-provisioning during low-traffic periods, so the solution must automatically reduce capacity when demand drops while preserving the ability to scale up. A target tracking scaling policy based on average CPU utilization continuously adjusts the desired instance count to maintain the target, scaling in during off-peak and out during peaks. This is the standard, hands-off cost-optimization approach for variable workloads.

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 10

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.. Migrating indices older than 30 days to UltraWarm nodes reduces storage costs because UltraWarm provides cost-effective storage for infrequently accessed data. This retains data for the full 90-day compliance period while keeping the last 30 days in hot storage for fast access. Option A is incorrect because moving logs to S3 Glacier would make querying impractical and is not designed for OpenSearch. Option B is incorrect because increasing data nodes would increase costs without addressing storage optimization. Option D is incorrect because deleting indices after 30 days would violate the 90-day retention requirement.

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 11

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.. Creating a read replica offloads read traffic from the primary instance, improving performance for read-heavy workloads. Using a smaller instance type for the replica reduces cost compared to scaling up the primary. Option A is wrong because Multi-AZ provides high availability via a standby instance that cannot serve reads; it does not improve read performance. Option B (increasing instance size) is a vertical scaling approach that increases cost without the same cost-efficiency as a read replica. Option C is incorrect because migrating to DynamoDB would require application changes and may not be compatible with the existing MySQL schema and queries.

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 12

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 allows visualization and filtering of costs by tags, accounts, and services, enabling cost allocation and identification of top cost drivers. AWS Organizations (A) is used to centrally manage policies and accounts but does not provide cost visualization. AWS Trusted Advisor (B) offers best practice recommendations but not detailed cost analysis. AWS Budgets (D) sets budget alerts but does not provide historical cost exploration or allocation.

Answer

AWS Organizations

Answer

AWS Trusted Advisor

Answer

AWS Budgets

Question 13

A company uses Amazon CloudFront to distribute content globally. The operations team notices that the data transfer costs are higher than expected. The origin server is an S3 bucket in us-east-1. Which change would reduce data transfer costs?

Accepted Answer

Enable compression for compressible content.. Enabling compression reduces the amount of data transferred from CloudFront to viewers, directly lowering data transfer costs. Option A (Lambda@Edge to resize images) can reduce image sizes but adds compute costs and may not be as effective as compression. Option B (increasing default TTL) reduces origin requests but does not reduce data transfer from CloudFront to viewers. Option C (multiple S3 buckets in different regions) increases complexity and may increase costs due to cross-region replication or multiple origins. Thus, D is the correct choice.

Answer

Use Lambda@Edge to resize images on the fly.

Answer

Increase the default TTL for objects.

Answer

Use multiple S3 buckets in different regions as origins.

Question 14

A SysOps administrator wants to receive alerts when the estimated charges for an AWS account exceed a certain threshold. Which AWS service should be used?

Accepted Answer

AWS Budgets. AWS Budgets enables you to set custom cost and usage budgets and receive alerts when your actual or forecasted costs exceed your budget thresholds. This is the correct service for receiving alerts on estimated charges. Option A (AWS Trusted Advisor) provides cost optimization recommendations but does not send billing alerts. Option B (AWS Cost Explorer) allows you to analyze your costs but does not send proactive alerts. Option C (Amazon CloudWatch billing metric) does have billing metrics, but to set alerts on those metrics you must use AWS Budgets; CloudWatch itself is not the service for budget alerts.

Answer

AWS Trusted Advisor

Answer

AWS Cost Explorer

Answer

Amazon CloudWatch (billing metric)

Question 15

A company is running a production web application on EC2 instances behind an ALB. The application experiences predictable traffic spikes during business hours. Which cost optimization strategy would be MOST effective?

Accepted Answer

Configure Scheduled Scaling to add instances before the spike and remove after.. The most effective cost optimization strategy because Scheduled Scaling allows you to increase capacity predictably before traffic spikes and decrease afterward, ensuring you only pay for what you need. Option B is incorrect because Spot Instances can be interrupted and are not suitable for production workloads that require high availability. Option C is incorrect because using larger instances does not dynamically adjust to spikes and may lead to over-provisioning during low traffic. Option D is incorrect because On-Demand instances are more expensive than using scheduled scaling with a mix of Reserved Instances or Savings Plans to cover the baseline and scheduled scaling for the spikes.

Answer

Use Spot Instances for the entire workload.

Answer

Use larger instance types to handle the spikes without scaling.

Answer

Use On-Demand instances exclusively to handle the spikes.