SOA-C02 Cost and Performance Optimization Practice Test 8 — 15 Questions

Question 1

A SysOps administrator is optimizing an AWS Lambda function that processes data from an S3 bucket. The function currently runs with 128 MB memory and a 5-second timeout. The function experiences timeouts for large files. The administrator wants to improve performance and reduce cost. Which TWO actions should they take?

Accepted Answer

Enable provisioned concurrency to reduce cold starts.. Options A and D are correct because increasing memory often reduces execution time and cost due to faster processing, and enabling reserved concurrency prevents cold starts and ensures capacity. Option B is wrong because increasing timeout alone does not improve performance and may increase cost. Option C is wrong because provisioning more functions does not affect a single function's performance. Option E is wrong because moving to S3 Standard-IA is for storage cost, not compute.

Answer

Increase the function timeout to 15 minutes.

Answer

Configure the S3 event notification to use S3 Standard-IA for the input files.

Answer

Create multiple Lambda functions to process different files concurrently.

Question 2

A company runs a web application on EC2 instances with an Auto Scaling group. The application uses an Amazon RDS MySQL database. During a traffic spike, the database CPU utilization reaches 90%. The SysOps team needs to improve database performance cost-effectively. Which THREE actions should they take?

Accepted Answer

Enable RDS Performance Insights to identify slow queries.. Options A, B, and D are correct because adding Read Replicas offloads read traffic, enabling RDS Performance Insights helps identify bottlenecks, and using RDS Proxy reduces connection overhead. Option C is wrong because vertical scaling (upgrading instance) is more expensive than horizontal scaling. Option E is wrong because Multi-AZ does not improve performance; it's for failover.

Answer

Enable Multi-AZ for the RDS instance.

Answer

Upgrade the RDS instance to a larger instance type.

Question 3

A company has three EC2 instances as shown in the exhibit. The company pays for a t3.micro Reserved Instance. Which instance(s) will receive the RI discount?

Accepted Answer

Only i-0abcd1234. Option A is correct because RI discounts apply to running instances of the same instance size (or size flexible family). The t3.micro RI covers t3.micro instances; the t3.medium is larger and not covered. The stopped instance does not run, so no discount. Option B is wrong because the stopped instance does not run. Option C is wrong because t3.medium is not covered. Option D is wrong because only the t3.micro running instance qualifies.

Answer

i-0abcd1234 and i-0abcd5678

Answer

i-0abcd1234 and i-0abcd9012

Answer

All three instances

Question 4

A company has an S3 bucket policy as shown. A developer tries to upload an object using the AWS CLI without the --no-verify-ssl flag. What will happen?

Accepted Answer

The upload will succeed because the CLI uses HTTPS by default.. Option A is correct because the policy denies requests that are not using secure transport (HTTPS). Since the CLI uses HTTPS by default, the request is allowed. Option B is wrong because the default is HTTPS. Option C is wrong because the policy denies HTTP, not HTTPS. Option D is wrong because the policy allows HTTPS requests.

Answer

The upload will succeed only if the developer uses HTTP.

Answer

The upload will fail because the policy denies all s3:* actions.

Answer

The upload will fail because the policy requires explicit HTTPS.

Question 5

A SysOps administrator reviews the CloudWatch metrics for an EC2 instance as shown. The instance is part of an Auto Scaling group with a target tracking scaling policy based on average CPU utilization set to 50%. During the time period shown, what is the expected behavior?

Accepted Answer

The Auto Scaling group will scale out because CPU utilization exceeded 50% for several consecutive data points.. Option C is correct because CPU utilization peaks at 95.1% at 00:20, exceeding the 50% target, so the Auto Scaling group should scale out. Option A is wrong because it does exceed the target. Option B is wrong because the average over the hour is around 47%, but the policy reacts to sustained breaches; the peak would trigger scaling. Option D is wrong because scaling would occur.

Answer

The Auto Scaling group will not scale because the average CPU utilization over the hour is below 50%.

Answer

The Auto Scaling group will scale in because the CPU utilization dropped below 50% at the end.

Answer

The Auto Scaling group will not scale because the metric shows a decline after the peak.

Question 6

A company runs a web application on EC2 instances behind an ALB. They want to optimize costs for variable traffic patterns while maintaining high availability. Which solution is MOST cost-effective?

Accepted Answer

Use a mix of On-Demand and Spot Instances in an Auto Scaling group with a target tracking scaling policy.. Option B is correct because using Spot Instances in an Auto Scaling group with a mix of On-Demand and Spot instances provides cost savings while maintaining availability. Option A is wrong because Reserved Instances require a 1- or 3-year commitment and are not flexible for variable traffic. Option C is wrong because Dedicated Hosts are more expensive and not needed for this use case. Option D is wrong because On-Demand only is more expensive than using Spot.

Answer

Use Dedicated Hosts to run the application and share resources across multiple accounts.

Answer

Purchase Reserved Instances for the expected baseline capacity and use On-Demand for spikes.

Answer

Use only On-Demand EC2 Instances with an Auto Scaling group to handle variable traffic.

Question 7

A SysOps administrator receives an AWS Budgets alert that the monthly cost for an S3 bucket has increased by 300% compared to the previous month. The bucket stores log files and uses S3 Standard storage. The bucket has versioning enabled and lifecycle policies that transition objects to S3 Glacier Deep Archive after 90 days. What is the MOST likely cause of the cost increase?

Accepted Answer

The cost of lifecycle transition requests to Glacier Deep Archive.. Option B is correct because S3 Lifecycle transition requests cost per object, and the transition to Glacier Deep Archive incurs a cost. Option A is wrong because S3 Standard storage costs are for the first 90 days, not the transition. Option C is wrong because object size is not mentioned as a change. Option D is wrong because data transfer costs are not typically associated with lifecycle transitions.

Answer

The increased storage costs due to S3 Standard storage for the first 90 days.

Answer

Data transfer costs for downloading logs from the bucket.

Answer

The cost of storing multiple versions of objects due to versioning.

Question 8

A company is using AWS CloudFormation to deploy infrastructure. They want to reduce costs by identifying unused resources. Which AWS service should they use to monitor and report on resource utilization and cost?

Accepted Answer

AWS Trusted Advisor. Option D is correct because AWS Trusted Advisor provides cost optimization checks, including idle resources. Option A is wrong because AWS Config tracks configuration changes, not cost. Option B is wrong because CloudTrail logs API activity, not cost. Option C is wrong because CloudWatch monitors performance, not cost optimization.

Answer

AWS Config

Answer

Amazon CloudWatch

Answer

AWS CloudTrail

Question 9

A company runs a production database on a db.r5.large RDS instance with Multi-AZ enabled. They notice that the CPU utilization is consistently below 10% and memory usage is below 20%. The application is not expected to grow significantly. Which action would optimize costs without sacrificing high availability?

Accepted Answer

Change the instance type to a smaller size, such as db.t3.medium, and keep Multi-AZ.. Option C is correct because the instance is over-provisioned; downsizing to a smaller instance type (e.g., db.r5.large to db.t3.medium) reduces cost. Multi-AZ should be retained for high availability. Option A is wrong because removing Multi-AZ sacrifices high availability. Option B is wrong because Reserved Instances require a commitment and may not be cost-effective if the instance type is changed. Option D is wrong because moving to a larger instance increases costs.

Answer

Remove Multi-AZ and use a single-AZ deployment to reduce costs.

Answer

Purchase a Reserved Instance for the current instance type to get a discount.

Answer

Change the instance type to a larger size, such as db.r5.xlarge, to improve performance.

Question 10

A company has a web application that uses an Application Load Balancer (ALB) and an Auto Scaling group of EC2 instances. The Auto Scaling group uses a dynamic scaling policy based on average CPU utilization. The SysOps administrator notices that during traffic spikes, the scaling policy adds instances too slowly, causing performance degradation. Which action should the administrator take to improve performance without significantly increasing costs?

Accepted Answer

Change the scaling policy to a target tracking policy with a target CPU utilization of 70%.. Option A is correct because a target tracking policy with a higher CPU threshold (e.g., 70%) can be more responsive than a step scaling policy. Option B is wrong because increasing the cooldown period would slow scaling down further. Option C is wrong because using a simple scaling policy with a higher threshold may not be as responsive. Option D is wrong because a scheduled scaling policy is not suitable for unpredictable spikes.

Answer

Use a scheduled scaling policy to add instances during known peak hours.

Answer

Increase the cooldown period for the scaling policy to allow instances to warm up.

Answer

Switch to a simple scaling policy that scales out when CPU exceeds 80%.

Question 11

A SysOps administrator is reviewing the monthly AWS bill and notices a significant cost for data transfer from EC2 to the internet. The EC2 instances are in a VPC and serve content to users. Which action would MOST effectively reduce data transfer costs?

Accepted Answer

Use Amazon CloudFront as a content delivery network (CDN).. Option C is correct because CloudFront caches content at edge locations, reducing data transfer from EC2 to the internet. Option A is wrong because using a NAT Gateway adds cost. Option B is wrong because VPC endpoints are for private connectivity to AWS services, not for reducing internet data transfer. Option D is wrong because moving to a different region does not reduce data transfer costs.

Answer

Use VPC endpoints to connect to S3 and DynamoDB.

Answer

Move the EC2 instances to a different AWS Region with lower data transfer rates.

Answer

Use a NAT Gateway to route traffic through a single IP.

Question 12

A company runs a batch processing job every night that takes 2 hours on a single m5.xlarge EC2 instance. The job is fault-tolerant and can be interrupted. The SysOps administrator wants to reduce costs. Which solution is MOST cost-effective?

Accepted Answer

Use a Spot Instance with a Spot Fleet that includes a fallback to On-Demand if Spot is not available.. Option D is correct because using Spot Instances with a fleet and fallback to On-Demand provides cost savings while ensuring the job completes. Option A is wrong because Reserved Instances require a commitment and may not be cost-effective for a 2-hour daily job. Option B is wrong because Dedicated Hosts are expensive. Option C is wrong because using only On-Demand is more expensive than using Spot.

Answer

Use an On-Demand instance and set up a CloudWatch alarm to stop it when the job completes.

Answer

Use a Dedicated Host to run the job.

Answer

Purchase a Reserved Instance for the m5.xlarge instance.

Question 13

A company has an S3 bucket that stores millions of small objects (1-10 KB) and uses S3 Standard storage. The bucket receives frequent PUT requests and occasional GET requests. The monthly bill shows high costs for S3 PUT requests. Which action would reduce costs?

Accepted Answer

Aggregate small objects into larger files (e.g., 1 MB) before uploading to S3.. Option C is correct because aggregating small objects into larger files reduces the number of PUT requests, which are billed per request. Option A is wrong because S3 Intelligent-Tiering is for storage cost, not request cost. Option B is wrong because S3 Glacier is for archival, and PUT requests to Glacier cost more. Option D is wrong because lifecycle policies do not reduce PUT request costs.

Answer

Move the objects to S3 Glacier Deep Archive to reduce storage cost.

Answer

Move the objects to S3 Intelligent-Tiering to optimize storage costs.

Answer

Use S3 Lifecycle policies to transition objects to S3 Standard-IA after 30 days.

Question 14

A SysOps administrator wants to monitor the cost and usage of AWS resources for different departments. Which AWS service should they use to tag resources and generate cost allocation reports?

Accepted Answer

AWS Cost Explorer with cost allocation tags. Option B is correct because AWS Cost Explorer with cost allocation tags allows filtering by tags. Option A is wrong because AWS Budgets sets alerts, not reporting. Option C is wrong because AWS Trusted Advisor provides optimization recommendations. Option D is wrong because AWS Config tracks configuration, not cost.

Answer

AWS Trusted Advisor

Answer

AWS Budgets

Answer

AWS Config

Question 15

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 reserved instances offer significant discounts. Option C is correct because rightsizing to a smaller instance reduces cost if the current instance is over-provisioned. Option B is wrong because removing Multi-AZ sacrifices high availability. Option D is wrong because moving to a single-AZ also sacrifices availability. Option E is wrong because enabling auto scaling is not a feature of RDS for cost optimization.

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.