SOA-C02 Cost and Performance Optimization Practice Test 12 — 15 Questions

Question 1

A company is using AWS Cost Explorer to analyze spending. They want to receive an email alert when costs exceed a certain threshold. Which service should they use?

Accepted Answer

AWS Budgets. AWS Budgets can send alerts when costs exceed thresholds. Option A (AWS Trusted Advisor) is wrong because it provides recommendations for cost optimization but does not send alerts based on cost thresholds. Option B (AWS Cost Explorer) is wrong because it is used for analyzing cost and usage data, not for sending alerts. Option C (Amazon CloudWatch) is wrong because CloudWatch monitors AWS resources and applications, but it does not natively monitor AWS costs or send cost threshold alerts.

Answer

AWS Trusted Advisor

Answer

AWS Cost Explorer

Answer

Amazon CloudWatch

Question 2

A company has an EC2-based application that runs at inconsistent times. The workloads are fault-tolerant and can be interrupted. Which purchasing option provides the most cost savings?

Accepted Answer

Spot Instances. Spot Instances. Spot Instances offer the largest discount (up to 90%) for workloads that are fault-tolerant and can be interrupted. Reserved Instances (A) require a 1- or 3-year commitment and are best for steady-state workloads. On-Demand Instances (B) provide no discount. Dedicated Hosts (C) are expensive and designed for specific licensing or compliance requirements, not cost savings.

Answer

Reserved Instances

Answer

On-Demand Instances

Answer

Dedicated Hosts

Question 3

A SysOps administrator is troubleshooting high CPU utilization on an RDS for MySQL instance. The application is read-heavy. Which optimization technique would improve performance and potentially reduce costs?

Accepted Answer

Implement RDS Read Replicas to offload read traffic.. Implementing RDS Read Replicas offloads read traffic from the primary instance to one or more replicas, reducing CPU utilization on the primary. This improves performance for read-heavy applications and can also reduce costs because you can potentially use a smaller primary instance or fewer replicas than scaling up the primary. Read Replicas are asynchronous and can be in different AZs or regions.

Answer

Delete unused indexes from the database.

Answer

Increase the allocated storage size.

Answer

Enable Multi-AZ deployment for failover support.

Question 4

A company wants to monitor the performance of its EC2 instances and receive alerts when CPU utilization exceeds 80% for 10 minutes. Which AWS service should be used?

Accepted Answer

Amazon CloudWatch. Amazon CloudWatch can monitor CPU utilization metrics for EC2 instances and trigger alarms when a threshold (e.g., 80% for 10 minutes) is exceeded. Option B (AWS CloudTrail) is wrong because it records API activity, not performance metrics. Option C (AWS Config) is wrong because it evaluates resource configurations, not performance. Option D (VPC Flow Logs) is wrong because it captures network traffic information, not CPU usage.

Answer

AWS CloudTrail

Answer

AWS Config

Answer

VPC Flow Logs

Question 5

A company stores infrequently accessed data in S3 Standard. They want to reduce storage costs without compromising immediate accessibility. What is the MOST cost-effective solution?

Accepted Answer

Use S3 Standard-IA storage class.. The most cost-effective solution is to use S3 Standard-IA (Option B). S3 Standard-IA is designed for infrequently accessed data that requires immediate access; it offers lower storage costs than S3 Standard while maintaining low latency and high throughput. Option A (S3 Glacier Flexible Retrieval) has even lower storage cost but retrieval times of minutes to hours, which does not meet the requirement of immediate accessibility. Option C (S3 Intelligent-Tiering) automatically moves data between tiers to optimize costs, but it includes monitoring and automation charges that may not be cost-effective for data that is consistently infrequently accessed; also, it does not guarantee lower cost than Standard-IA for this pattern. Option D (create a lifecycle policy to delete after 30 days) would lose data permanently and is not a storage class; it also does not address cost savings for long-term storage.

Answer

Use S3 Glacier Flexible Retrieval.

Answer

Move data to S3 Intelligent-Tiering.

Answer

Create a lifecycle policy to delete objects after 30 days.

Question 6

A company is using Amazon CloudFront to deliver content globally. Which feature can help reduce costs by minimizing data transfer from the origin?

Accepted Answer

Configure caching to serve content from edge locations.. Configuring caching in CloudFront allows content to be served from edge locations, reducing the number of requests that need to go to the origin. This minimizes data transfer from the origin and lowers costs. Option A is incorrect because multiple origins are for routing different content, not for reducing origin transfer; load balancing doesn't inherently reduce data transfer costs. Option C is incorrect because custom SSL certificates secure connections but do not affect data transfer costs. Option D is incorrect because Lambda@Edge runs custom code at edge locations but does not directly reduce the volume of data transferred from the origin; it may even add compute costs.

Answer

Enable multiple origins for load balancing.

Answer

Configure custom SSL certificates.

Answer

Use Lambda@Edge to process requests.

Question 7

A company is running a high-performance computing (HPC) workload on EC2. The workload is time-sensitive and runs for 2 hours every night. The company wants to minimize costs. Which THREE options should they consider? (Choose THREE.)

Accepted Answer

Use an EFS or S3 as shared storage instead of EBS volumes.. Options B, C, and E are correct. B is correct because using EFS or S3 as shared storage reduces costs compared to attaching individual EBS volumes to each instance. C is correct because using smaller instance types in parallel can be more cost-effective for HPC workloads that can be parallelized. E is correct because Spot Instances offer significant discounts for fault-tolerant workloads like HPC. Option A is incorrect because Reserved Instances require a 1-3 year commitment and would not be cost-effective for a 2-hour nightly job. Option D is incorrect because Dedicated Instances are more expensive and not necessary for this workload.

Answer

Purchase Reserved Instances for the nightly run.

Answer

Use Dedicated Instances for performance isolation.

Question 8

A company wants to monitor the performance of its application running on EC2. Which TWO metrics should be monitored to detect performance bottlenecks? (Choose TWO.)

Accepted Answer

CPU Utilization. To detect performance bottlenecks on EC2, you should monitor CPU Utilization (B) and Memory Utilization (E). High CPU utilization indicates CPU-bound issues, while high memory utilization can cause swapping and degrade performance. Network Packets In (A) is a network metric but not typically a direct performance bottleneck indicator. Status Check Failed (C) is for instance health, not performance. Disk Space Utilization (D) is a storage capacity metric, not a performance metric, and is not available by default (requires custom scripts).

Answer

Network Packets In

Answer

Status Check Failed

Answer

Disk Space Utilization

Question 9

A company is running a web application on a fleet of EC2 instances behind an Application Load Balancer. The application experiences variable traffic patterns with predictable spikes every day at 2 PM. The company wants to optimize costs while maintaining performance. Which solution is MOST cost-effective?

Accepted Answer

Use scheduled scaling to add instances before the spike and remove them after.. Scheduled scaling is the correct answer because the traffic spikes are predictable and occur at a known time (2 PM daily). Scheduled scaling allows you to define a schedule (using cron expressions) to automatically increase the desired capacity of the Auto Scaling group before the spike and decrease it afterward, ensuring performance while minimizing costs during off-peak hours. This is more cost-effective than manual scaling because it eliminates the need for human intervention and ensures instances are only running when needed.

Answer

Use manual scaling by adjusting the desired capacity each day at 2 PM.

Answer

Purchase Reserved Instances for the entire fleet to reduce costs.

Answer

Use dynamic scaling policies based on CPU utilization.

Question 10

A company uses Amazon S3 to store log files. The logs are accessed frequently for the first 30 days, then rarely accessed after that. The company must retain logs for 7 years for compliance. What is the MOST cost-effective storage solution?

Accepted Answer

Use S3 Standard for 30 days and then transition to S3 Glacier Deep Archive.. S3 Lifecycle policies can transition objects from S3 Standard to S3 Glacier Deep Archive after 30 days, minimizing costs while meeting compliance. S3 Glacier Flexible Retrieval is more expensive than Deep Archive for long-term archival. S3 Intelligent-Tiering adds monitoring costs. S3 One Zone-IA is not suitable for long-term archival due to lower durability.

Answer

Use S3 Standard for 7 years.

Answer

Use S3 One Zone-IA for 30 days and then transition to S3 Glacier Flexible Retrieval.

Answer

Use S3 Intelligent-Tiering for the entire 7 years.

Question 11

A company uses Amazon CloudWatch to monitor its AWS resources. The company wants to receive alerts when CPU utilization of an EC2 instance exceeds 80% for 5 consecutive minutes. What is the MOST efficient way to achieve this?

Accepted Answer

Create a CloudWatch alarm on the CPUUtilization metric with a threshold of 80% for 5 consecutive periods.. A CloudWatch alarm on the CPUUtilization metric with a threshold of 80% for 5 consecutive periods (each period being 1 minute) directly monitors the metric and triggers an alert when the condition is met. This is the most efficient and native way to achieve the requirement, as it requires no custom code or log parsing.

Answer

Use CloudWatch Logs to parse CPU utilization from system logs and trigger an alert.

Answer

Use Amazon EventBridge to schedule a Lambda function that checks CPU utilization.

Answer

Use AWS CloudTrail to monitor EC2 instance metrics.

Question 12

A company runs a batch processing job on Amazon EMR every night. The job runs for 6 hours and requires a cluster of 20 m5.xlarge instances. The company wants to reduce costs while ensuring the job completes on time. Which solution is MOST cost-effective?

Accepted Answer

Use Spot Instances for core and task nodes and an On-Demand instance for the primary node.. Amazon EMR clusters consist of a primary node (master), core nodes (which run HDFS and task processes), and task nodes (which only run tasks and can be lost without data loss). Spot Instances are ideal for task nodes because they can be interrupted without affecting HDFS data, and for core nodes if the cluster is resilient to interruptions (e.g., using EMRFS consistent view or if the job can tolerate some core node loss). The primary node must be On-Demand to avoid cluster termination if the Spot Instance is reclaimed. This mix minimizes cost while ensuring the job completes on time.

Answer

Use On-Demand instances for all nodes.

Answer

Purchase Reserved Instances for the entire cluster.

Answer

Use Spot Instances for the primary node and On-Demand for core and task nodes.

Question 13

A company is using Amazon S3 to host a static website. The website receives millions of requests per month from users around the world. The company wants to reduce latency and S3 data transfer costs. Which solution should the company implement?

Accepted Answer

Use Amazon CloudFront as a content delivery network in front of the S3 bucket.. Amazon CloudFront is a content delivery network that caches content at edge locations, reducing latency and data transfer costs from S3. S3 Transfer Acceleration speeds up uploads but not downloads. S3 Replication does not reduce latency. S3 Cross-Region Replication is for data redundancy, not performance.

Answer

Enable S3 replication to multiple regions.

Answer

Enable S3 Transfer Acceleration.

Answer

Use S3 Cross-Region Replication to replicate objects to all regions.

Question 14

A company wants to optimize costs for its Amazon EC2 instances. Which TWO strategies are effective for reducing costs?

Accepted Answer

Use Spot Instances for fault-tolerant workloads.. Using Spot Instances for fault-tolerant workloads can reduce costs significantly (up to 90%). Rightsizing instances ensures you are not paying for unused capacity. Dedicated Hosts increase costs. Increasing provisioned IOPS increases costs. Using EBS General Purpose SSD (gp3) is cost-effective but not a primary cost reduction strategy.

Answer

Increase the provisioned IOPS for EBS volumes.

Answer

Use EBS General Purpose SSD (gp2) volumes instead of gp3.

Answer

Use Dedicated Hosts to meet compliance requirements.

Question 15

A company runs a web application on EC2 instances in an Auto Scaling group. The application experiences variable traffic. The company wants to improve performance and reduce costs. Which THREE actions should the company take?

Accepted Answer

Implement dynamic scaling policies based on CPU utilization.. Option A is correct because dynamic scaling policies based on CPU utilization let the Auto Scaling group add instances when demand rises and remove them when demand falls, directly improving performance during peaks while reducing cost during troughs. Option C is correct because an Application Load Balancer distributes incoming HTTP/HTTPS traffic across healthy instances and connection draining (deregistration delay) allows in-flight requests to complete before an instance is terminated during scale-in, preventing errors and improving availability. Option D is correct because mixing On-Demand and Spot Instances in the Auto Scaling group lowers compute costs by using discounted Spot capacity for fault-tolerant portions of the workload while On-Demand instances provide baseline reliability. Option B is not appropriate because simply reducing the number of instances lowers capacity and would degrade performance under variable traffic rather than improve it. Option E is not appropriate because increasing instance size (vertical scaling) is less elastic and typically more expensive than horizontal scaling, and it does not efficiently match variable traffic or reduce costs.

Answer

Reduce the number of instances in the Auto Scaling group to lower costs.

Answer

Increase the instance size to handle peak load.