SOA-C02 Cost and Performance Optimization Practice Test 13 — 15 Questions

Question 1

A company wants to reduce costs for its Amazon S3 storage. Which TWO strategies are effective?

Accepted Answer

Use S3 Lifecycle policies to transition objects to S3 Glacier Deep Archive after a period.. S3 Lifecycle policies transition objects to lower-cost storage classes. S3 Object Tagging helps organize data but does not directly reduce costs. S3 Transfer Acceleration increases costs. S3 Replication increases costs. S3 Intelligent-Tiering can be cost-effective for unknown access patterns.

Answer

Enable S3 Object Tagging to categorize data.

Answer

Enable S3 Replication to another region for disaster recovery.

Answer

Enable S3 Transfer Acceleration for faster uploads.

Question 2

An administrator runs the above CloudWatch command to analyze CPU utilization for an EC2 instance. The instance is currently running with a t3.large instance type. The company wants to optimize costs. Based on the data, which action should the administrator take?

Accepted Answer

Downsize the instance to t3.medium to reduce costs.. The average CPU utilization over the week is low (around 15.5%), indicating the instance is over-provisioned. Downsizing to a t3.medium (half the vCPUs and memory) would likely be sufficient and reduce costs. Reserved Instances would be cost-effective only if the instance runs consistently, but the current utilization is low. Scaling up would increase costs. Stopping the instance is not an option if needed.

Answer

Stop the instance to save costs immediately.

Answer

Scale up the instance to t3.xlarge to improve performance.

Answer

Purchase a Reserved Instance for the current instance type.

Question 3

A company runs a web application on EC2 instances with Elastic Load Balancing. They notice that costs are higher than expected. What is the MOST cost-effective way to optimize costs while maintaining high availability?

Accepted Answer

Use a combination of Reserved Instances for baseline traffic and On-Demand for spikes.. Reserved Instances provide a significant discount (up to ~72% versus On-Demand) in exchange for a one- or three-year commitment, making them ideal for the predictable baseline load. On-Demand instances then absorb traffic spikes without a long-term commitment, so the workload stays highly available while the blended cost is minimized. This hybrid model is the standard AWS cost-optimization pattern for steady-state web tiers behind an ELB.

Answer

Use Spot Instances for all traffic.

Answer

Use On-Demand instances for all traffic.

Answer

Reduce the number of instances to one.

Question 4

An application runs on EC2 instances behind an ALB. Users report slow response times. CPU utilization averages 90% during peak hours. What is the MOST effective way to improve performance?

Accepted Answer

Increase the instance size to a larger type.. Increasing the instance size (scaling up) provides more CPU resources directly, addressing the high utilization. While Auto Scaling could add more instances, the question specifically asks about the given options, and D is the most effective among them. Detailed monitoring (A) only provides metrics, not performance improvement. Memory-optimized (B) does not help CPU-bound issues. Security group rules (C) do not affect compute performance.

Answer

Enable detailed monitoring on CloudWatch.

Answer

Switch to a memory-optimized instance type.

Answer

Add more Security Group rules.

Question 5

A SysOps administrator wants to monitor the cost of EC2 instances. Which AWS service should be used to visualize and track costs over time?

Accepted Answer

AWS Cost Explorer. AWS Cost Explorer is the dedicated cost management tool that provides visualization of historical and forecasted AWS spending, including EC2 costs, through graphs, filters, and grouping by service, tag, or linked account. It ingests the Cost and Usage Report data and lets administrators track spend trends over time, which is exactly what the question asks for.

Answer

AWS CloudWatch

Answer

AWS Budgets

Answer

AWS Trusted Advisor

Question 6

A company uses S3 standard storage for all data. They have data that is accessed rarely but must be retained for 7 years. Which storage class would be MOST cost-effective?

Accepted Answer

S3 Glacier Deep Archive. S3 Glacier Deep Archive is the lowest-cost storage for long-term archival. S3 Standard is expensive, S3 IA is for infrequent access but not long-term, and S3 One Zone IA is less durable.

Answer

S3 One Zone-IA

Answer

S3 Standard

Answer

S3 Intelligent-Tiering

Question 7

A SysOps administrator notices that a Lambda function is timing out after 30 seconds. The function processes large files from S3. How can the administrator improve performance while minimizing cost?

Accepted Answer

Increase the memory allocation of the Lambda function.. Increasing the memory allocation of the Lambda function also proportionally increases the allocated CPU power, which directly reduces the execution time for CPU-bound tasks like processing large files. This often resolves timeout issues without incurring additional cost per invocation, as the cost is a product of memory and duration, and a faster execution can offset the higher memory price.

Answer

Increase the timeout value to 5 minutes.

Answer

Enable Provisioned Concurrency.

Answer

Deploy the function on an EC2 instance.

Question 8

An application uses an RDS MySQL DB instance. The administrator notices that read performance is poor during peak hours. What is a cost-effective way to improve read performance?

Accepted Answer

Create a read replica in the same region.. Creating a read replica offloads read traffic from the primary RDS instance, improving read performance during peak hours at a relatively low cost. Option A (ElastiCache) adds complexity and additional cost. Option B (Multi-AZ) is for high availability and disaster recovery, not for read performance. Option C (scaling up) addresses performance but is more expensive than adding a read replica.

Answer

Use Amazon ElastiCache for caching.

Answer

Enable Multi-AZ deployment.

Answer

Scale up the DB instance to a larger size.

Question 9

A company wants to receive alerts when their monthly AWS spending exceeds $1,000. Which AWS service should be used?

Accepted Answer

AWS Budgets. AWS Budgets allows setting cost thresholds and alerts. CloudWatch alarms are for metrics, not budgets. Cost Explorer is for visualization. Trusted Advisor provides recommendations.

Answer

AWS Trusted Advisor

Answer

AWS CloudWatch

Answer

AWS Cost Explorer

Question 10

An application writes logs to an S3 bucket. The logs are accessed frequently for the first 30 days, then rarely after that, but must be retained for 7 years. Which THREE steps should be taken to optimize cost? (Choose three.)

Accepted Answer

Use an S3 Lifecycle policy to transition objects to S3 Glacier Deep Archive after 90 days.. S3 Glacier Deep Archive is the lowest-cost storage class for long-term archival data, making it ideal for logs that are rarely accessed after 90 days. An S3 Lifecycle policy automates the transition from a higher-cost class (e.g., Standard-IA) to Glacier Deep Archive, reducing storage costs while retaining the data for the required 7-year period.

Answer

Delete logs older than 30 days.

Answer

Use S3 Intelligent-Tiering to automatically optimize costs.

Question 11

Which TWO AWS services can be used to monitor the performance of an EC2 instance?

Accepted Answer

AWS Systems Manager. Amazon CloudWatch is the primary service for monitoring EC2 performance metrics like CPU utilization, network, and disk I/O. AWS Systems Manager can also collect performance data through Inventory and Run Command, providing operational insights. AWS CloudTrail logs API activity for auditing, not performance. AWS Trusted Advisor offers cost and security recommendations. AWS Config tracks configuration changes, not performance metrics.

Answer

AWS CloudTrail

Answer

AWS Trusted Advisor

Answer

AWS Config

Question 12

A SysOps administrator needs to reduce costs for a non-production environment that runs 24/7 but is only used during business hours. What is the MOST effective action?

Accepted Answer

Create a schedule to stop instances after business hours and start them before.. Creating a schedule to stop instances after business hours and start them before business hours is the most effective cost-saving action because it directly reduces the hours the instances run, which is the primary cost driver for EC2. Since the environment is only used during business hours, stopping instances during off-hours eliminates unnecessary compute charges. This approach is simple, requires no architectural changes, and yields immediate savings.

Answer

Switch all instances to Spot Instances.

Answer

Purchase Reserved Instances for the environment.

Answer

Reduce the instance sizes to the smallest available.

Question 13

A company wants to monitor the performance of its Amazon RDS for MySQL database. The database is experiencing high CPU utilization during peak hours. The SysOps administrator needs to identify the queries causing the load. Which AWS service should be used?

Accepted Answer

Amazon RDS Performance Insights. Amazon RDS Performance Insights provides a dashboard that visualizes database load and helps identify the queries causing high CPU usage. Option B is wrong because AWS CloudTrail records API activity, not database query performance data. Option C is wrong because Amazon Inspector is a vulnerability management service, not a database performance tool. Option D is wrong because Amazon CloudWatch Logs collects log files but does not analyze query performance or CPU usage impact.

Answer

AWS CloudTrail

Answer

Amazon Inspector

Answer

Amazon CloudWatch Logs

Question 14

A SysOps administrator is troubleshooting slow application performance. The application runs on Amazon EC2 instances in an Auto Scaling group behind an Application Load Balancer. Amazon CloudWatch metrics show that the average CPU utilization across the instances is below 20%, but the application is still slow. What is the MOST likely cause of the performance issue?

Accepted Answer

The application database is under-provisioned and is causing slow query responses.. The most likely cause is that the application database is under-provisioned, leading to slow query responses. Even though EC2 CPU utilization is low, the application performance is bottlenecked by database latency. This is a common scenario where the database tier is the constraint, not the compute tier.

Answer

The Auto Scaling group is scaling too aggressively, causing thrashing.

Answer

The Application Load Balancer has a sticky session configuration that is not distributing traffic evenly.

Answer

The EC2 instances are using burstable performance and have exhausted their CPU credits.

Question 15

A company is using AWS Lambda functions to process events from Amazon S3. The functions are invoked several thousand times per minute. The SysOps administrator notices that the functions are taking longer to execute during peak times. Which action should the administrator take to improve performance?

Accepted Answer

Increase the memory allocation for the Lambda functions.. Increasing the memory allocation for a Lambda function also proportionally increases its CPU allocation, which can improve execution speed for compute-bound tasks, such as processing events from S3 during peak times. Option A is incorrect because increasing the timeout only allows the function to run longer, but does not make it faster. Option B is incorrect because Lambda abstracts the underlying infrastructure; you cannot choose EC2 instance types. Option D is incorrect because provisioned concurrency reduces cold starts but does not affect the execution time of warm functions.

Answer

Increase the Lambda function timeout.

Answer

Use a larger EC2 instance type for the Lambda functions.

Answer

Enable provisioned concurrency on the Lambda functions.