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

Question 1

A company is running a stateful web application on EC2 instances in an Auto Scaling group. The application requires low latency and high throughput. Currently, the application is experiencing performance degradation during peak hours. Which scaling strategy should the SysOps administrator implement to improve performance and optimize cost?

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

Accepted Answer

Predictive scaling policy. Predictive scaling is the correct choice because it uses machine learning to analyze historical traffic patterns and proactively adjust capacity before demand spikes, which is ideal for a stateful web application experiencing predictable peak-hour performance degradation. This approach ensures low latency and high throughput by pre-warming instances, while optimizing cost by avoiding over-provisioning during off-peak periods.

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Step scaling policy based on memory utilization

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Scheduled scaling with fixed times

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Simple scaling policy based on CPU utilization

Question 2

A company wants to reduce data transfer costs for traffic between EC2 instances in the same AWS Region. Which action should the SysOps administrator take?

Accepted Answer

Ensure instances communicate using private IP addresses within the same VPC. Traffic between EC2 instances in the same VPC using private IP addresses does not incur public internet data transfer costs. If the instances are in the same Availability Zone, the traffic is free; if they are in different Availability Zones, standard inter-AZ data transfer charges apply. Using private IPs is still the most cost-effective option compared to using public IPs (Elastic IPs) or routing through a NAT Gateway.

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Use Elastic IP addresses for all instances

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Place instances in public subnets and route traffic through a NAT Gateway

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Use VPC endpoints to communicate between instances

Question 3

A company has multiple AWS accounts and wants to centrally track costs and usage across all accounts. Which AWS service should the SysOps administrator use?

Accepted Answer

AWS Organizations. AWS Organizations enables centralized management of multiple AWS accounts, including consolidated billing and cost tracking. By using the management account, you can view aggregated costs and usage across all member accounts through AWS Cost Explorer and Cost & Usage Reports, making it the correct service for this requirement.

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AWS Budgets

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AWS Config

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AWS Trusted Advisor

Question 4

A company is running a critical application on Amazon RDS for MySQL. The database is experiencing high read traffic, causing performance issues. The SysOps administrator needs to improve read performance while keeping costs low. Which solution should the administrator choose?

Accepted Answer

Add one or more Read Replicas in the same Region. Adding one or more Read Replicas in the same Region offloads read traffic from the primary RDS instance by directing SELECT queries to the replicas, which are asynchronous copies of the primary. This directly addresses high read traffic without incurring the cost of a larger instance or the complexity of caching, making it the most cost-effective solution for read scaling.

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Enable Multi-AZ deployment

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Increase the DB instance class to a larger size

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Use Amazon ElastiCache to cache read results

Question 5

A company stores log files in Amazon S3. The logs are accessed frequently for the first 30 days, then rarely after that. The company wants to automatically transition objects to a lower-cost storage class after 30 days. Which S3 feature should be configured?

Accepted Answer

S3 Lifecycle rule. An S3 Lifecycle rule is the correct feature because it allows you to define a transition action that automatically moves objects from a higher-cost storage class (e.g., S3 Standard) to a lower-cost storage class (e.g., S3 Standard-IA or S3 Glacier) after a specified number of days. This directly meets the requirement to transition logs after 30 days without manual intervention, optimizing storage costs based on access patterns.

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S3 Versioning

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S3 Transfer Acceleration

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S3 Object Lock

Question 6

A company is using Amazon S3 to store media files. The files are accessed frequently for the first 90 days, then rarely after that. The company wants to optimize storage costs. Which TWO actions should the SysOps administrator take? (Choose two.)

Accepted Answer

Configure a lifecycle policy to delete incomplete multipart uploads after 7 days. Configuring a lifecycle policy to delete incomplete multipart uploads after 7 days prevents orphaned parts from incurring storage costs. Option C is correct because creating a lifecycle policy to transition objects to S3 Standard-IA after 90 days reduces storage costs for infrequently accessed data. Option B is incorrect because S3 Object Lock is used for compliance and retention, not cost optimization. Option D is incorrect because enabling S3 Versioning can increase storage costs by retaining multiple versions of objects. Option E is incorrect because enabling Requester Pays shifts the cost of requests and data transfer to the requester, but does not optimize storage costs for the company.

Answer

Enable S3 Object Lock to prevent deletion

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Enable S3 Versioning to keep multiple versions

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Enable Requester Pays on the bucket

Question 7

A company runs a production database on Amazon RDS for PostgreSQL. The SysOps administrator wants to improve query performance for a read-heavy application without increasing costs significantly. Which THREE actions should the administrator take? (Choose three.)

Accepted Answer

Optimize slow queries by reviewing the slow query log. Reviewing the slow query log in RDS for PostgreSQL allows the administrator to identify and optimize poorly performing queries, which directly improves query performance without incurring additional infrastructure costs. This is a standard performance tuning practice that targets the root cause of read-heavy application slowdowns.

Answer

Enable Multi-AZ deployment

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Increase the allocated storage size

Question 8

A SysOps administrator is troubleshooting a cost overrun in an AWS account. The cost explorer shows that data transfer costs have significantly increased. The architecture includes an Application Load Balancer (ALB) internet-facing, EC2 instances in private subnets, and an S3 bucket for static assets. Which action will MOST effectively reduce data transfer costs?

Accepted Answer

Implement a VPC Gateway Endpoint for S3 so that traffic from EC2 to S3 stays within the AWS network.. Implementing a VPC Gateway Endpoint for S3 allows EC2 instances in private subnets to access S3 without traversing the NAT Gateway or internet, eliminating data transfer costs associated with NAT Gateway data processing and internet egress. This is the most effective cost reduction because S3 traffic is often a major contributor to data transfer charges in such architectures.

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Enable Amazon CloudFront to cache static assets and reduce direct requests to the ALB.

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

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Change the ALB to internal (private) and use AWS Direct Connect for user access.

Question 9

A company is running a stateful web application on EC2 instances in an Auto Scaling group. The application requires low latency and high throughput. Currently, the application is experiencing performance degradation during peak hours. Which scaling strategy should the SysOps administrator implement to improve performance and optimize cost?

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.

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

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

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

Question 10

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.

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

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

Question 11

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.

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

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

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Launch a Dedicated Host to ensure consistent performance.

Question 12

A SysOps administrator notices that the monthly bill for Amazon S3 has increased significantly. The company uses S3 for storing application logs and user uploads. The logs are accessed rarely but must be retained for 3 years. User uploads are accessed frequently for the first 30 days, then rarely after. Which S3 lifecycle policy will optimize storage costs?

Accepted Answer

Transition logs to S3 Glacier Deep Archive after 30 days, and transition user uploads to S3 Standard-IA after 30 days, then to Glacier Deep Archive after 90 days.. The correct policy matches storage class to access patterns: logs are rarely accessed but retained for three years, so transitioning them to Glacier Deep Archive after 30 days minimizes cost for long-term archival. User uploads are frequently accessed for 30 days, then rarely, so moving them to Standard-IA after 30 days and then to Glacier Deep Archive after 90 days aligns cost with declining access frequency while preserving durability. This combination addresses both data types with the cheapest suitable tiers.

Answer

Transition user uploads to S3 Glacier Deep Archive after 30 days, and transition logs to S3 Glacier after 90 days.

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Move logs to S3 Glacier Deep Archive after 30 days, and delete user uploads after 1 year.

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Transition logs to S3 Standard-IA after 30 days, and transition user uploads to S3 One Zone-IA after 30 days.

Question 13

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 transitioning them to Glacier Deep Archive after 30 days is the most cost-effective compliant solution because CloudWatch Logs storage is significantly more expensive per GB than S3, and Glacier Deep Archive costs roughly $0.00099/GB-month versus CloudWatch Logs at ~$0.03/GB-month. This preserves the 1-year retention requirement while cutting storage costs by over 90%.

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Reduce the log retention period to 30 days.

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

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

Question 14

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.. The administrator needs to diagnose the database bottleneck before making changes. RDS Performance Insights provides detailed visibility into database load, wait events, and top SQL statements, allowing identification of slow queries or resource contention. This aligns with the goal of improving performance without over-provisioning, as it enables targeted optimization rather than guessing at scaling. The other options either add unnecessary resources or don't address the root cause.

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Add a Read Replica to offload read queries.

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Convert the RDS instance to a Multi-AZ deployment.

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Increase the RDS instance size to the next tier.

Question 15

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.

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Use larger instance types to improve performance.

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Enable detailed CloudWatch monitoring for all instances.

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Enable termination protection on all instances.