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

Question 1

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 2

A company has a production environment with multiple EC2 instances. They want to ensure that all instances are covered by a Reserved Instance (RI) to maximize cost savings. Which AWS service can automatically apply unused RIs to new instances?

Accepted Answer

AWS Cost Explorer. None of the listed services automatically apply unused Reserved Instances (RIs) to new instances. The application of unused RIs is handled automatically by AWS billing. AWS Cost Explorer provides RI utilization reports and recommendations, but does not apply RIs. AWS Systems Manager manages operational tasks, AWS Trusted Advisor offers best practice checks, and AWS Config evaluates resource configurations. None of these services perform automatic RI application.

Answer

AWS Systems Manager

Answer

AWS Trusted Advisor

Answer

AWS Config

Question 3

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 4

A company is using a t3.medium EC2 instance for a development web server. The instance is underutilized most of the time. Which TWO actions would optimize costs? (Choose TWO.)

Accepted Answer

Downsize the instance to t3.small.. Options B and C are correct. Option B (Downsize the instance to t3.small) reduces compute capacity and cost for an underutilized workload, directly lowering hourly costs. Option C (Purchase a Reserved Instance) provides a significant discount over On-Demand pricing for steady-state usage like a development server that runs continuously. Option A (Enable EBS optimization) does not reduce costs—it adds a fee for dedicated throughput. Option D (Change the instance to On-Demand) is already On-Demand; changing does not save money. Option E (Use Spot Instances) is unsuitable because development servers often need consistent availability, and Spot Instances can be interrupted, risking workload disruption.

Answer

Enable EBS optimization.

Answer

Change the instance to On-Demand.

Answer

Use Spot Instances for the workload.

Question 5

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 6

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 7

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 allows you to add capacity in advance of the predictable spike, ensuring performance during the spike and reducing costs by running only needed instances at other times. Dynamic scaling reacts to real-time metrics, which may cause a temporary performance lag. Manual scaling is not automated. Reserved Instances provide a discount but do not adjust capacity automatically.

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 8

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 9

A company is using AWS Direct Connect to connect its on-premises data center to AWS. The company notices that data transfer costs are increasing. The company wants to reduce data transfer costs without impacting performance. Which action should the company take?

Accepted Answer

Use Direct Connect gateway to connect to multiple VPCs across regions.. A Direct Connect gateway allows you to connect to multiple VPCs in different AWS Regions using a single Direct Connect connection. This consolidation reduces the number of separate connections and virtual interfaces, thereby lowering overall data transfer costs because you avoid paying for multiple connections' data transfer charges. In contrast, VPC endpoints reduce data transfer costs only for traffic to S3 and DynamoDB, not for general data transfer. Increasing bandwidth or adding VPN encryption does not reduce costs.

Answer

Increase the bandwidth of the Direct Connect connection to improve performance.

Answer

Set up a VPN connection over the Direct Connect to encrypt traffic.

Answer

Use VPC endpoints for S3 and DynamoDB to reduce data transfer costs.

Question 10

A company runs a production database on an Amazon RDS for PostgreSQL instance. The company notices that the database is experiencing high CPU utilization during peak hours, causing performance degradation. The company wants to improve performance while minimizing cost. Which solution should the company implement?

Accepted Answer

Add an Amazon RDS read replica to offload read traffic.. Adding a read replica offloads read traffic from the primary instance, reducing CPU utilization. Read replicas are cost-effective and can be promoted if needed. Scaling up the instance type increases cost and may not be necessary. Multi-AZ provides high availability but does not reduce CPU load. ElastiCache would require application changes and adds cost.

Answer

Create a Multi-AZ deployment for high availability.

Answer

Implement Amazon ElastiCache in front of the database.

Answer

Scale up the DB instance class to a larger size.

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 can be set to trigger when the CPUUtilization metric exceeds 80% for 5 consecutive minutes (e.g., 5 evaluation periods of 1 minute each). This is the native and efficient way. CloudWatch Logs is for log data. CloudTrail is for API activity. EventBridge is for event-driven actions but requires a more complex setup.

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 has a stateful web application that requires session persistence. The application is deployed on EC2 instances behind an Application Load Balancer. The company wants to improve performance by caching frequently accessed data. Which solution is MOST cost-effective?

Accepted Answer

Use Amazon ElastiCache with Memcached to cache session data and frequently accessed data.. ElastiCache with Memcached is a cost-effective in-memory caching solution that can improve performance by caching frequently accessed data. It supports session storage. ELB sticky sessions (Session Affinity) ensure requests from the same user go to the same instance, but do not cache data. Increasing instance size improves performance but at a higher cost. CloudFront caches content at the edge, not application data.

Answer

Increase the instance size of the EC2 instances to improve performance.

Answer

Use Amazon CloudFront to cache static and dynamic content at the edge.

Answer

Enable sticky sessions (Session Affinity) on the ALB.

Question 13

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.. Using Spot Instances for the core and task nodes can significantly reduce costs, as Spot Instances are often much cheaper than On-Demand. The primary node should be On-Demand to avoid disruption. Using all On-Demand is more expensive. Reserved Instances are for steady-state workloads, not short-term jobs. Instance fleets can mix instance types but do not inherently reduce costs like Spot.

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 14

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 15

A company runs a critical application on an Amazon RDS for MySQL DB instance. The company needs to ensure high availability and automatic failover in the event of a failure. The company also wants to optimize costs. Which solution should the company implement?

Accepted Answer

Create a Multi-AZ deployment for the RDS instance.. Multi-AZ deployment provides automatic failover to a standby instance in a different Availability Zone, ensuring high availability. It is cost-effective compared to a manual standby. A read replica does not provide automatic failover. An RDS proxy improves connection pooling but not failover. Using a larger instance increases cost without adding redundancy.

Answer

Create a read replica in a different Availability Zone and manually promote it during failure.

Answer

Use Amazon RDS Proxy to manage connections and improve failover.

Answer

Use a larger DB instance class to improve performance and reliability.