SOA-C02 Cost and Performance Optimization Practice Test 4 — 15 Questions

Question 1

A company runs a critical application on EC2 instances in an Auto Scaling group behind an Application Load Balancer. The application requires very low latency and high availability. The SysOps administrator notices that the application experiences increased latency during traffic spikes even though the Auto Scaling group is scaling out. Which solution would MOST effectively reduce latency?

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

Accepted Answer

Change the launch configuration to use a larger instance type with more CPU and memory.. Using a larger instance type with more CPU and memory directly addresses the root cause of increased latency during traffic spikes: the existing instances are resource-constrained under load. By provisioning instances with higher compute capacity, each instance can handle more requests per second, reducing queueing delays and per-request processing time. This is a more immediate and effective solution than scaling out alone, which adds instances but does not improve the performance of each individual instance.

Answer

Pre-warm the load balancer by contacting AWS Support.

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Increase the Auto Scaling cooldown period.

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Deploy the instances in multiple Availability Zones.

Question 2

A company is running a web application on EC2 instances behind an Application Load Balancer. The application experiences variable traffic patterns. The SysOps team wants to optimize costs without impacting performance. Which EC2 purchasing option should the team use for the instances?

Accepted Answer

Savings Plans. Savings Plans offer flexible pricing across EC2 instance families and regions, providing significant discounts (up to 72%) compared to On-Demand. With variable traffic, they allow cost savings without requiring a specific instance configuration or long-term commitment to a particular instance type. The plan applies to any EC2 usage, making it ideal for workloads with unpredictable or changing patterns, while performance remains unaffected since instances still run as On-Demand.

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Spot Instances

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On-Demand Instances

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Reserved Instances

Question 3

A SysOps administrator notices that the monthly bill for Amazon RDS is higher than expected. The environment includes multiple DB instances with low CPU and memory utilization. Which action will most effectively reduce costs while maintaining performance?

Accepted Answer

Resize the DB instances to a smaller instance class. The DB instances have low CPU and memory utilization, indicating they are over-provisioned. Resizing to a smaller instance class directly reduces the hourly compute cost without affecting performance, as the current workload does not require the larger instance's capacity.

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Enable Multi-AZ deployment for high availability

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Delete unused RDS snapshots

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Provisioned IOPS (io1) storage for better performance

Question 4

A company uses S3 Standard for all data, but some objects are accessed only once per year. Which storage class provides the lowest cost for this use case while maintaining the same durability?

Accepted Answer

S3 Glacier Deep Archive. S3 Glacier Deep Archive provides the lowest storage cost for data accessed once per year, with the same 99.999999999% (11 nines) durability as S3 Standard, because it is designed for long-term retention with retrieval times of 12 hours or more. The infrequent access pattern makes the lower retrieval costs of Glacier Deep Archive more economical than any other S3 storage class.

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S3 One Zone-Infrequent Access (S3 One Zone-IA)

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S3 Intelligent-Tiering

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S3 Standard-Infrequent Access (S3 Standard-IA)

Question 5

A SysOps team is using CloudWatch to monitor CPU utilization of EC2 instances. They want to receive a notification when average CPU exceeds 80% for 5 consecutive minutes. Which combination of services should they use?

Accepted Answer

CloudWatch Metrics, CloudWatch Alarm, and Amazon SNS. CloudWatch Metrics collects the CPU utilization data from EC2 instances, a CloudWatch Alarm evaluates whether the average CPU exceeds 80% for 5 consecutive minutes (using a period of 300 seconds and 5 datapoints), and Amazon SNS publishes the notification to subscribers (e.g., email, SMS) when the alarm state transitions to ALARM. This combination directly fulfills the requirement without unnecessary services.

Answer

CloudWatch Metrics, CloudWatch Alarm, and AWS Lambda

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AWS Config, CloudWatch Alarm, and Amazon SNS

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CloudWatch Logs, CloudWatch Alarm, and AWS Lambda

Question 6

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?

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 7

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.

Answer

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 8

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 9

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.

Answer

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 10

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 11

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 12

A SysOps administrator is designing a cost-effective architecture for a batch processing workload that runs once per day and can tolerate interruptions. The workload uses EC2 instances. Which TWO purchasing options should the administrator consider? (Choose two.)

Accepted Answer

Spot Instances. (Spot Instances) is correct because they offer significant cost savings and are ideal for fault-tolerant, interruptible workloads like a batch job that runs once per day. Option C (On-Demand Instances) is correct as a fallback to ensure the workload can run even if Spot capacity is unavailable. Option A is incorrect because Dedicated Hosts are expensive and not necessary for a batch processing workload. Option D is incorrect because Reserved Instances require a 1- or 3-year commitment, which is not cost-effective for a once-daily job. Option E is incorrect because Capacity Reservations incur costs even when not running, making them unsuitable for an interruptible workload.

Answer

Dedicated Hosts

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Reserved Instances (Standard)

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Capacity Reservations

Question 13

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

Answer

Increase the allocated storage size

Question 14

A company runs a production web application on Amazon EC2 instances behind an Application Load Balancer. The application experiences variable traffic patterns, with peak usage during business hours. The company wants to optimize costs while maintaining performance. What should the SysOps administrator do?

Accepted Answer

Use a combination of On-Demand and Spot Instances, with On-Demand for baseline traffic and Spot for burst capacity.. A combination of On-Demand and Spot Instances allows the company to handle variable traffic cost-effectively: On-Demand Instances cover baseline traffic with guaranteed availability, while Spot Instances provide burst capacity at lower cost. Option A is wrong because increasing instance sizes for peak load leads to over-provisioning and higher costs during off-peak times. Option B is wrong because Reserved Instances require a 1- or 3-year commitment and are not cost-effective for variable traffic since they run all the time. Option D is wrong because Dedicated Hosts are expensive and unnecessary for this workload; they provide physical isolation, not cost optimization.

Answer

Increase the EC2 instance sizes to handle peak load at all times.

Answer

Purchase Reserved Instances for all instances to get the lowest hourly rate.

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Use Dedicated Hosts to ensure consistent performance.

Question 15

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.. A VPC Gateway Endpoint for S3 allows EC2 instances in private subnets to access S3 without traversing the internet or a NAT gateway, eliminating data transfer costs for S3 traffic. Option A is incorrect because CloudFront reduces latency and offloads requests from the ALB, but data transfer from ALB to EC2 still incurs costs. Option C is incorrect because NAT Gateway charges are for data processing and transfer, and replacing it with a NAT instance may reduce hourly charges but does not address data transfer costs to S3. Option D is incorrect because making the ALB internal prevents direct internet access, requiring a VPN or Direct Connect, which adds costs.

Answer

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

Answer

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

Answer

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