SOA-C02 Cost and Performance Optimization Practice Test 5 — 15 Questions

Question 1

A company is running a stateful web application on a single EC2 instance with a 500 GB gp2 EBS volume. The instance is currently at 80% CPU and memory utilization during peak hours. The company wants to improve performance and scalability without incurring high costs. What should the SysOps administrator do?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Implement an Application Load Balancer with an Auto Scaling group to distribute traffic across multiple instances.. Implementing an Application Load Balancer (ALB) with an Auto Scaling group allows the application to scale horizontally (scale out) based on demand. This improves both performance and scalability while optimizing costs because you only pay for the resources you use. Option B (vertical scaling) is incorrect because upgrading to a larger instance may require downtime and does not provide the same level of scalability; it also might be more costly. Option C (increasing swap space) is a temporary fix that does not address the root cause of high CPU and memory utilization; excessive swapping can degrade performance. Option D (migrating to gp3) improves I/O performance but does not help with CPU or memory constraints, and it does not enable scalability.

Answer

Upgrade the instance to a larger size (vertical scaling).

Answer

Increase the swap space on the instance to handle memory pressure.

Answer

Migrate the EBS volume from gp2 to gp3 to improve I/O performance.

Question 2

A company has a production RDS for PostgreSQL database with a db.r5.large instance. The database experiences high read traffic during business hours. The SysOps administrator needs to improve read performance and ensure high availability at minimal cost. Which solution should the administrator implement?

Accepted Answer

Create a Multi-AZ deployment and then add a Read Replica in a different Availability Zone.. A Multi-AZ deployment provides high availability by automatically failing over to a standby in a different AZ. Adding a Read Replica in another AZ offloads read traffic, improving read performance. Option A is costly because upgrading the instance size does not provide high availability and only vertically scales compute. Option C is incorrect because Multi-AZ alone does not help with read scaling; it only provides failover. Option D introduces additional complexity and cost with ElastiCache, which is not a direct database solution and may not be minimal cost compared to a Read Replica within RDS.

Answer

Upgrade the instance to db.r5.xlarge and enable automatic backups.

Answer

Enable Multi-AZ on the existing instance to provide automatic failover but no read scaling.

Answer

Use Amazon ElastiCache for Redis to cache frequent queries.

Question 3

A SysOps administrator is reviewing AWS Cost Explorer and notices that data transfer costs from EC2 to the internet are high. The EC2 instances are in a VPC with a NAT Gateway in a public subnet. The route table for private subnets sends 0.0.0.0/0 traffic to the NAT Gateway. The application serves content to users over the internet. Which change will LEAST impact application performance while reducing costs?

Accepted Answer

Implement a VPC Gateway Endpoint for Amazon S3 to keep S3 traffic within AWS.. The high data transfer costs are from EC2 to internet for serving content to users. This traffic flows through the NAT Gateway to the internet. A VPC Gateway Endpoint for Amazon S3 only affects traffic between EC2 and S3, not internet traffic. Therefore C would not reduce the costs described. Options A would reduce costs but may impact performance; B is for IPv6 only; D is not a real service. Thus, none of the options correctly solves the problem. The question needs to be revised, perhaps offering a solution like CloudFront or public subnets with public IPs.

Answer

Replace the NAT Gateway with a smaller NAT Gateway to reduce hourly charges.

Answer

Use an egress-only Internet Gateway for the private subnets.

Answer

Purchase a Dedicated NAT Gateway in the same region to get lower data processing rates.

Question 4

A company runs a batch processing job on a single EC2 instance that runs for 2 hours every night. The job is fault-tolerant and can be interrupted. The SysOps administrator wants to minimize compute costs. What is the MOST cost-effective solution?

Accepted Answer

Use a Spot Instance that can be interrupted but is significantly cheaper.. A Spot Instance is the most cost-effective choice because the job is fault-tolerant and can be interrupted, allowing you to leverage unused AWS EC2 capacity at up to 90% discount compared to On-Demand pricing. Since the job runs for only 2 hours nightly and can handle interruptions, Spot Instances provide the lowest compute cost while meeting the workload requirements.

Answer

Use an On-Demand instance to ensure the job runs every night.

Answer

Purchase a Reserved Instance for 1 year to get a discount.

Answer

Launch a Dedicated Host to ensure consistent performance.

Question 5

A company uses Amazon CloudWatch Logs to store application logs from EC2 instances. The log volume is 100 GB per day, and logs are retained for 1 year. The SysOps administrator wants to reduce costs while maintaining compliance. Which solution is MOST effective?

Accepted Answer

Export logs to Amazon S3 and configure a lifecycle policy to transition them to Glacier Deep Archive after 30 days.. Exporting logs to Amazon S3 and configuring a lifecycle policy to transition them to Glacier Deep Archive after 30 days significantly reduces storage costs while still retaining logs for compliance (1 year). Option A is incorrect because reducing the retention period to 30 days would violate the 1-year compliance requirement. Option B is incorrect because disabling server-side encryption does not lower costs meaningfully and poses security risks. Option C is incorrect because CloudWatch Logs Insights is a query tool, not a storage mechanism; it cannot replace storing logs.

Answer

Reduce the log retention period to 30 days.

Answer

Disable server-side encryption for the log group to reduce overhead.

Answer

Use CloudWatch Logs Insights to query logs instead of storing them.

Question 6

A company has a web application running on EC2 instances behind an Application Load Balancer. The application experiences latency spikes during peak hours. Amazon CloudWatch metrics show that CPU and memory are not fully utilized. The SysOps administrator suspects the bottleneck is the database. The database is an RDS for MySQL instance. Which action should the administrator take to improve performance without over-provisioning?

Accepted Answer

Enable RDS Performance Insights to analyze database load and identify slow queries.. RDS Performance Insights helps identify database bottlenecks such as slow queries and locks, allowing targeted optimization. Option A (Read Replica) offloads read traffic but doesn't help if the bottleneck is writes or locking. Option B (Multi-AZ) improves availability, not performance. Option D (increasing instance size) may over-provision without addressing the root cause.

Answer

Add a Read Replica to offload read queries.

Answer

Convert the RDS instance to a Multi-AZ deployment.

Answer

Increase the RDS instance size to the next tier.

Question 7

A SysOps administrator is optimizing costs for an AWS account. The account has multiple EC2 instances running 24/7 with varying utilization. Which TWO actions will help reduce costs without impacting performance? (Choose TWO.)

Accepted Answer

Use AWS Compute Optimizer to right-size instances.. AWS Compute Optimizer analyzes historical utilization metrics (CPU, memory, network, etc.) and provides right-sizing recommendations to match instance types to actual workload demands. By downsizing over-provisioned instances, you reduce costs without degrading performance, as the new instance type still meets the workload's peak requirements.

Answer

Use larger instance types to improve performance.

Answer

Enable detailed CloudWatch monitoring for all instances.

Answer

Enable termination protection on all instances.

Question 8

A company uses Amazon S3 to store backups and logs. The total data volume is 50 TB and grows by 2 TB per month. The company requires that data be retained for 7 years. Which THREE actions will optimize storage costs? (Choose THREE.)

Accepted Answer

Use S3 Lifecycle policies to transition data to S3 Glacier Deep Archive after 30 days.. The correct answers are A, B, and D. S3 Lifecycle policies help optimize storage costs. Option A transitions data to S3 Glacier Deep Archive, the lowest-cost storage class for long-term retention. Option B expires incomplete multipart uploads, preventing unnecessary storage charges. Option D uses S3 Intelligent-Tiering, which automatically moves data between tiers based on changing access patterns, reducing costs for infrequently accessed data with unknown patterns. Option C is incorrect because deleting data after one year fails to meet the 7-year retention requirement. Option E is incorrect because S3 Glacier Flexible Retrieval is more expensive than S3 Glacier Deep Archive and is not necessary for data that is rarely accessed.

Answer

Store all data in S3 Standard for the first year, then delete.

Answer

Use S3 Glacier Flexible Retrieval to allow data retrieval in minutes.

Question 9

A SysOps administrator reviews the CloudWatch metric data for an EC2 instance. The instance runs a web application that experiences high traffic between 12:00 and 14:00 UTC daily. The administrator wants to optimize costs while maintaining performance. What should the administrator do?

Accepted Answer

Create an Auto Scaling group with a scheduled scaling policy to add instances during peak hours.. The instance has low CPU utilization most of the day but spikes to 90% during peak hours. Using a scheduled Auto Scaling to add instances during peak hours ensures performance without over-provisioning. Option A is wrong because the instance is not constantly at high utilization. Option B is wrong because upgrading instance size increases cost during off-peak hours. Option D is wrong because a larger instance would be underutilized.

Answer

Convert the instance to a Reserved Instance to reduce hourly cost.

Answer

Replace the instance with a larger instance type and enable detailed monitoring.

Answer

Increase the instance size to handle peak load at all times.

Question 10

A SysOps administrator attached the IAM policy shown to a user. The user needs to launch EC2 instances for a cost-sensitive project. What is the impact of this policy on cost optimization?

Accepted Answer

The policy allows launching any number of t3.micro instances, potentially increasing costs if many instances are launched.. The policy restricts the instance type to t3.micro, which is a low-cost instance, but it does not impose any limit on the number of instances that can be launched. Therefore, a user could launch many t3.micro instances, and while each individual instance is cheap, the cumulative cost could become significant, potentially increasing costs rather than optimizing them. Option B is incorrect because the question is about cost optimization, not workload adequacy. Option C is incorrect because the condition on RunInstances allows launching instances as long as the instance type is t3.micro; it does not block launches. Option D is incorrect because cost control depends on both instance type and number of instances; allowing unlimited quantity undermines cost optimization.

Answer

The policy is too restrictive because it only allows t3.micro instances, which may not be sufficient for production workloads.

Answer

The policy does not allow launching any instances because the condition is on RunInstances.

Answer

The policy ensures cost control by allowing only t3.micro instances, which are the cheapest.

Question 11

A SysOps administrator reviews the Lambda invocation metrics for a function. The function processes data from an S3 bucket and is triggered by S3 events. The cost for this function is higher than expected. What should the administrator do to reduce costs?

Accepted Answer

Increase the function's memory allocation to reduce execution time.. Increasing the function's memory allocation provides more CPU resources, which typically reduces execution time. Lambda pricing is based on the product of memory and duration. If the reduction in duration is proportionally greater than the increase in memory, the total cost per invocation decreases. This is a common cost optimization strategy. Option A is incorrect because reserved concurrency limits the number of concurrent executions but does not reduce total invocations or cost per invocation. Option B is incorrect because changing to a scheduled invocation would cause the function to miss S3 events, likely breaking the application. Option D is incorrect because reducing memory allocation would likely increase execution time, resulting in higher total cost due to increased duration.

Answer

Set a reserved concurrency limit to cap the number of concurrent executions.

Answer

Change the function to be invoked on a schedule instead of by S3 events.

Answer

Reduce the function's memory allocation to lower cost per invocation.

Question 12

A company runs a web application on EC2 instances behind an Application Load Balancer. The application experiences variable traffic patterns. What is the MOST cost-effective way to ensure the application scales based on demand?

Accepted Answer

Use EC2 Auto Scaling with a target tracking scaling policy based on average CPU utilization.. A target tracking scaling policy based on average CPU utilization automatically adjusts the number of EC2 instances to maintain a target metric (e.g., 50% CPU), scaling out during high demand and scaling in during low demand. This is the most cost-effective approach for variable traffic patterns as it eliminates over-provisioning and manual intervention, directly aligning capacity with real-time demand.

Answer

Provision a fixed number of EC2 instances that can handle peak load at all times.

Answer

Use EC2 Auto Scaling with a scheduled scaling policy that adds instances during business hours.

Answer

Use EC2 Auto Scaling with a manual scaling plan that requires an administrator to adjust the desired capacity.

Question 13

A company has a production RDS MySQL instance with 500 GB of gp2 storage. The database experiences high read traffic. The SysOps team needs to improve read performance at minimal cost. What should they do?

Accepted Answer

Create one or more RDS Read Replicas in the same region and direct read traffic to them.. Creating RDS Read Replicas in the same region offloads read queries from the primary instance, improving read performance cost-effectively. Horizontal scaling with replicas is typically cheaper and more scalable than vertical scaling. Option A is wrong: migrating to Aurora is more expensive and auto scaling is not the primary solution for read-heavy workloads. Option B is wrong: switching to gp3 and increasing IOPS improves storage performance, but the bottleneck is more likely database processing, not IOPS. Option C is wrong: upgrading to a larger instance type increases cost without the scalability of replicas and may require downtime.

Answer

Migrate the database to Amazon Aurora with Auto Scaling enabled.

Answer

Change the storage type to gp3 and increase IOPS.

Answer

Upgrade the DB instance to a larger instance type with more vCPUs.

Question 14

A company uses AWS Lambda functions to process messages from an SQS queue. The Lambda function is configured with a reserved concurrency of 100. The SQS queue receives unpredictable spikes of up to 10,000 messages per second. The function takes about 1 second to process a message. The SysOps team notices that during spikes, messages are being throttled and appear in the DLQ. How can the team resolve this while optimizing cost?

Accepted Answer

Increase reserved concurrency to 1000 and enable batch processing with a batch size of 10 in the SQS event source mapping.. Increasing reserved concurrency to 1000 allows the Lambda function to scale to handle the spike of 10,000 messages per second, and enabling batch processing with a batch size of 10 reduces the number of invocations, which optimizes cost by processing up to 10 messages per invocation instead of one. Option A is wrong because reducing reserved concurrency would throttle even more messages, increasing DLQ traffic. Option C is wrong because using EC2 adds operational overhead and does not leverage Lambda's serverless scaling, increasing complexity and cost. Option D is wrong because Lambda does not use instance types; memory and timeout adjustments do not directly address concurrency limitations or batch processing.

Answer

Reduce the reserved concurrency to 10 to force the function to process messages more slowly.

Answer

Provision an EC2 fleet to poll the SQS queue and invoke the Lambda function.

Answer

Increase the Lambda function memory and timeout to use a larger instance type.

Question 15

A company uses CloudFront to distribute content globally. They want to reduce data transfer costs and improve performance for users. What feature should they enable?

Accepted Answer

Enable Origin Shield to create a central caching layer.. Origin Shield creates a central caching layer that reduces the number of requests to origins, improves cache hit ratio, and reduces data transfer costs. Option A is wrong because multiple origins with failover is for high availability, not cost reduction. Option B is wrong because Lambda@Edge adds compute at edge but doesn't directly reduce data transfer costs. Option D is wrong because increasing TTL may increase cache hits but doesn't provide the centralized caching benefit of Origin Shield and may cause stale content.

Answer

Configure multiple origins with failover.

Answer

Enable Lambda@Edge to modify requests and responses.

Answer

Increase the TTL for cache behaviors to the maximum allowed value.