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

Question 1

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.. It directly reduces compute costs by stopping instances when not needed (outside business hours), which eliminates charges for idle resources. Option B (Spot Instances) may cause interruptions, making it unreliable for consistent availability. Option C (Reserved Instances) requires a long-term commitment unsuitable for non-production environments. Option D (reducing instance sizes) might not yield significant savings if instances are idle, and could degrade performance.

Answer

Switch all instances to Spot Instances.

Answer

Purchase Reserved Instances for the environment.

Answer

Reduce the instance sizes to the smallest available.

Question 2

A company runs a production web application on Amazon EC2 instances behind an Application Load Balancer. The application experiences unpredictable traffic spikes. The operations team wants to optimize costs while maintaining performance during spikes. Which solution is MOST cost-effective?

Accepted Answer

Use Compute Savings Plans for the baseline and run the spikes on On-Demand instances.. The most cost-effective solution because Compute Savings Plans offer a flexible discount (up to 66%) in exchange for a commitment to a consistent amount of compute usage ($/hour) for 1 or 3 years. This covers EC2, Lambda, and Fargate across any instance family, region, or OS. By applying Savings Plans to the baseline workload, the company can save significantly while using On-Demand instances to handle unpredictable spikes without interruption risk. Option A (Spot Instances) is incorrect because Spot instances can be interrupted with short notice, making them unsuitable for a production web application that requires high availability. Option C (Reserved Instances) is less flexible because they are tied to a specific instance family and region, which may not accommodate changes in instance types needed during spikes. Option D (Dedicated Hosts) is expensive and provides no cost optimization for variable workloads, as it bills by the host regardless of usage.

Answer

Use Spot Instances to handle the spikes.

Answer

Purchase Reserved Instances for the expected baseline capacity.

Answer

Use Dedicated Hosts for the entire workload.

Question 3

A SysOps administrator is reviewing cost reports and notices that costs for Amazon S3 have increased significantly. The bucket stores log files that are accessed once a month for auditing. The logs are written daily, and each object is about 10 MB. The company needs to keep logs for 7 years. Which action will optimize costs while meeting retention requirements?

Accepted Answer

Use an S3 Lifecycle policy to transition objects to S3 Glacier Deep Archive after 30 days and expire after 7 years.. S3 Lifecycle policies can automate the transition of objects to lower-cost storage classes after a specified period. For log files that are accessed rarely (once a month), transitioning to S3 Glacier Deep Archive after 30 days minimizes storage costs while still meeting the 7-year retention requirement (expiration after 7 years). Option B is incorrect because Amazon EBS volumes are not designed for durable, cost-effective long-term storage of log files and would be more expensive. Option C is incorrect because S3 Glacier Flexible Retrieval is more expensive than S3 Glacier Deep Archive for long-term archival storage. Option D is incorrect because storing logs in S3 Standard for 7 years would incur high costs; a lifecycle policy to transition to cheaper storage is more cost-effective.

Answer

Store the logs in an Amazon EBS volume.

Answer

Transition the logs to S3 Glacier Flexible Retrieval after 30 days.

Answer

Store the logs in S3 Standard and delete after 7 years.

Question 4

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 5

A company has a data processing job that runs on Amazon EMR. The job takes 2 hours to complete and runs once per day. The SysOps administrator wants to reduce costs without affecting the completion time. Which strategy is MOST effective?

Accepted Answer

Use Spot Instances for the task nodes in the EMR cluster.. The most cost-effective strategy is to use Spot Instances for the task nodes in the EMR cluster. Task nodes are fault-tolerant because they only process data and do not store persistent data. Spot Instances offer significant discounts (up to 90%) compared to On-Demand instances. Since the job runs for 2 hours, it is short enough that the risk of interruption is manageable, and EMR can automatically relaunch tasks if interrupted. Option B (smaller number of larger instances) may reduce parallelism and could increase runtime, potentially not meeting the 2-hour requirement. Option C (reducing core nodes) would affect HDFS storage and may increase job duration. Option D (Compute Savings Plans) would require a 1- or 3-year commitment and may not be optimal for a single daily job; Spot Instances provide greater savings without commitment.

Answer

Use a smaller number of larger EC2 instances.

Answer

Reduce the number of core nodes.

Answer

Purchase Compute Savings Plans for the EMR cluster.

Question 6

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.

Question 7

A SysOps administrator is managing a fleet of Amazon EC2 instances that run a batch processing job. The job runs for 30 minutes every hour. The administrator wants to optimize costs by using Spot Instances but must ensure that the job completes even if Spot Instances are interrupted. Which configuration should the administrator use?

Accepted Answer

Use a mixed instances policy with both On-Demand and Spot Instances, and configure the Spot allocation strategy to 'lowestPrice'.. A mixed instances policy with both On-Demand and Spot Instances provides a safety net: the On-Demand capacity ensures the job can continue even if Spot Instances are interrupted. The 'lowestPrice' allocation strategy optimizes cost by selecting the cheapest Spot Instances, and since the job runs for only 30 minutes each hour, the risk of interruption is low and any interruption can be absorbed by the On-Demand instances. This configuration balances cost savings with job completion guarantees.

Answer

Launch Spot Instances in an Auto Scaling group with a capacity-optimized allocation strategy.

Answer

Use a Spot Fleet with a 'persistent' request type.

Answer

Use only On-Demand Instances to avoid interruptions.

Question 8

A company uses Amazon CloudFront to distribute content globally. The SysOps administrator notices that the origin load is high and the cache hit ratio is low. What should the administrator do to improve the cache hit ratio and reduce origin load?

Accepted Answer

Increase the minimum, maximum, and default TTL values for the cache behavior.. Increasing the minimum, maximum, and default TTL values ensures that objects are cached for longer periods, which increases the likelihood of cache hits and reduces the load on the origin server. Option A (changing origin protocol policy to HTTPS only) does not affect caching behavior. Option B (adding an additional origin server) distributes load but does not directly improve cache hit ratio. Option C (enabling compression) reduces the size of transferred data but does not increase cache hits; it can even reduce caching efficiency if not configured properly.

Answer

Change the origin protocol policy to HTTPS only.

Answer

Add an additional origin server.

Answer

Enable compression for the content.

Question 9

A SysOps administrator is optimizing costs for an Amazon RDS for PostgreSQL instance. The database is used for a reporting application that runs only during business hours (9 AM to 5 PM). Which TWO actions should the administrator take to reduce costs? (Choose TWO.)

Accepted Answer

Stop the database instance during non-business hours.. Correct options: A and E. Option A is correct because stopping the database during non-business hours (e.g., at night and on weekends) eliminates compute and storage costs for that period, directly reducing costs for a reporting application used only during business hours. Option E is correct because switching from Multi-AZ to Single-AZ deployment removes the standby replica, which cuts costs by roughly half for the database instance. Option B (larger instance) increases costs, not reduces them. Option C (increased IOPS) also increases costs. Option D (Reserved Instance) requires a 1- or 3-year commitment, which is not cost-effective for a database that is stopped for significant periods; it would result in paying for unused capacity.

Answer

Move to a larger instance type to handle peaks.

Answer

Increase the provisioned IOPS for better performance.

Answer

Purchase a Reserved Instance for the database instance.

Question 10

A company runs a web application on Amazon EC2 instances behind an Application Load Balancer (ALB). The ALB is configured with a target group that has health checks. The application is experiencing intermittent 503 errors. The SysOps administrator needs to identify the root cause. Which THREE steps should the administrator take to diagnose the issue? (Choose THREE.)

Accepted Answer

Monitor the CloudWatch metric 'HealthyHostCount' for the target group.. Correct options: B, D, E. Option B is correct because monitoring the CloudWatch metric 'HealthyHostCount' for the target group helps determine if the number of healthy instances drops, which can cause 503 errors. Option D is correct because enabling and reviewing ALB access logs can reveal the client IPs and response codes to diagnose the intermittent 503 errors. Option E is correct because checking the target group health check logs helps identify if instances are failing health checks, leading to no healthy targets. Option A is wrong because security group rules for the ALB control allowed traffic but do not directly cause 503 errors; 503 errors typically indicate no healthy targets. Option C is wrong because increasing the unhealthy threshold makes the ALB less sensitive to failures but does not diagnose the root cause.

Answer

Check the security group rules for the ALB.

Answer

Increase the unhealthy threshold count in the health check settings.

Question 11

A SysOps administrator wants to reduce the cost of storing infrequently accessed data in Amazon S3. The data must be retained for 10 years for compliance. Which TWO actions should the administrator take? (Choose TWO.)

Accepted Answer

Use S3 Glacier Deep Archive as the destination for the lifecycle transition.. Correct options: A and D. Option A is correct because S3 Glacier Deep Archive is the cheapest storage class for long-term archival, ideal for 10-year compliance retention. Option D is correct because configuring an S3 Lifecycle policy to transition objects to S3 Glacier Deep Archive after 30 days reduces costs for infrequently accessed data. Option B is wrong because S3 Standard is expensive for infrequently accessed data and not suitable for long-term archiving. Option C is wrong because enabling S3 Versioning increases storage costs due to multiple versions and does not directly reduce costs. Option E is wrong because S3 Intelligent-Tiering has monitoring costs and is best for unknown access patterns; it does not automatically transition to Glacier Deep Archive.

Answer

Store the data in S3 Standard.

Answer

Enable S3 Versioning to protect against accidental deletion.

Answer

Use S3 Intelligent-Tiering to automatically optimize costs.

Question 12

A company runs a critical application on a fleet of EC2 instances that process real-time financial transactions. The application requires consistent low latency. The SysOps administrator notices that the application's latency increases periodically due to noisy neighbors. The administrator wants to optimize performance predictability. Which instance type should the administrator choose?

Accepted Answer

Dedicated Instances. Dedicated Instances run on hardware dedicated to a single customer, eliminating the noisy neighbor effect. Option A is wrong because Burstable Performance Instances (T3) are designed for variable workloads and do not provide consistent performance. Option C is wrong because Spot Instances are not suitable for critical, latency-sensitive applications. Option D is wrong because Reserved Instances provide a discount but do not isolate the instance from other customers.

Answer

Burstable Performance Instances (T3)

Answer

Spot Instances

Answer

Reserved Instances

Question 13

A company hosts a multi-tier web application on AWS. The application consists of an Application Load Balancer (ALB), a fleet of Amazon EC2 instances running in an Auto Scaling group, and an Amazon RDS for MySQL database. The application is accessed by users worldwide. Recently, the company has expanded to new geographic regions, and users in those regions are experiencing high latency. The SysOps administrator is tasked with optimizing performance for global users while keeping costs low. The administrator has already implemented Amazon CloudFront as a CDN for static content. However, dynamic content that requires database queries is still slow. The application's Auto Scaling group is configured with a dynamic scaling policy based on average CPU utilization, but the scaling is not responsive enough during traffic spikes, causing performance degradation. Additionally, the database is a single db.r5.large instance in the us-east-1 region, and all traffic must hit that database, causing high latency for remote users. The administrator needs to propose a comprehensive solution that addresses both compute and database performance issues globally, while considering cost. Which solution is MOST effective?

Accepted Answer

Use Amazon Aurora Global Database to create read replicas in other regions, and configure the Auto Scaling group with a target tracking scaling policy based on request count per target.. Amazon Aurora Global Database provides low-latency read replicas in other regions for dynamic content, reducing latency for global users. Additionally, a target tracking scaling policy based on request count per target is more responsive to traffic spikes than CPU-based scaling, as it directly reflects application load. Option A is wrong because using step scaling based on memory utilization does not address global latency and memory may not be the bottleneck. Option C is wrong because ElastiCache caching reduces database load but does not reduce latency for users far from the primary database; predictive scaling may not handle sudden spikes well. Option D is wrong because using larger instances and Multi-AZ does not reduce global latency and increases cost.

Answer

Increase the minimum and maximum size of the Auto Scaling group and use a step scaling policy based on memory utilization.

Answer

Implement Amazon ElastiCache for Redis to cache database queries, and use predictive scaling for the Auto Scaling group.

Answer

Use larger EC2 instances (e.g., c5.2xlarge) for the application tier and provision a Multi-AZ RDS instance for better performance.

Question 14

A company runs a data analytics platform on AWS that processes large datasets using Amazon EMR. The EMR cluster consists of 1 master node (m5.xlarge) and 10 core nodes (r5.2xlarge). The cluster runs batch jobs that last 4 hours each, and the cluster is terminated after each job. The SysOps administrator notices that the cluster takes 15 minutes to provision and bootstrap before each job, which increases the total runtime and cost. The administrator wants to reduce the time and cost associated with cluster provisioning. The data is stored in Amazon S3, and the job scripts are stored in an S3 bucket. The administrator has considered using long-running clusters but is concerned about cost. Which approach should the administrator take to optimize both time and cost?

Accepted Answer

Use EMR Managed Scaling and keep the cluster running between jobs.. Using EMR Managed Scaling with a long-running cluster eliminates the 15-minute provisioning time for each job, as the cluster remains active. Managed Scaling automatically adjusts the number of core nodes based on workload demand, minimizing idle costs by scaling down when not in use. Option A is wrong because Spot Instances reduce cost but do not address provisioning time. Option C is wrong because a larger master node does not speed up bootstrapping; bootstrapping time is dominated by installing software and configurations on all nodes. Option D is wrong because Amazon FSx for Lustre is a high-performance file system that can improve I/O but does not reduce provisioning time and adds unnecessary cost and complexity.

Answer

Switch the core nodes to Spot Instances to reduce costs.

Answer

Use a larger master node instance type to speed up bootstrapping.

Answer

Use Amazon FSx for Lustre as the data store to reduce I/O time.

Question 15

A company hosts a static website on Amazon S3 with public read access. The website content is updated weekly. The SysOps administrator notices that the monthly S3 costs are higher than expected. The website receives about 10,000 requests per day, and each object is small (average 50 KB). The administrator wants to reduce costs without affecting the user experience. The website does not require HTTPS or custom domain at this time. Which action should the administrator take?

Accepted Answer

Place an Amazon CloudFront distribution in front of the S3 bucket.. Placing an Amazon CloudFront distribution in front of the S3 bucket reduces costs by caching content at edge locations, thereby reducing the number of GET requests to S3 and leveraging lower CloudFront data transfer rates. This does not affect user experience because cached content is served quickly. Option A is incorrect: enabling default encryption adds encryption but does not reduce costs; it may increase overhead slightly. Option B is incorrect: S3 Glacier Flexible Retrieval is designed for archival storage with high retrieval latency and costs, making it unsuitable for serving a static website. Option D is incorrect: enabling S3 Versioning increases storage costs by retaining multiple versions of objects, which does not lower expenses.

Answer

Enable default encryption for the S3 bucket.

Answer

Transition the objects to S3 Glacier Flexible Retrieval.

Answer

Enable S3 Versioning to prevent accidental deletions.