Architecting on AWS Certification Architecting on AWS Certification Cost Optimization & Performance Efficiency 2 — Questions and Answers
Question 1: What is the primary benefit of using Amazon Aurora Serverless v2 compared to a provisioned Aurora cluster for a variable-workload application?
- It provides a lower storage cost per GB
- It automatically scales compute capacity up and down based on demand, eliminating over-provisioning (Correct answer)
- It replicates data to three Regions automatically
- It eliminates the need for database backups
Correct answer: It automatically scales compute capacity up and down based on demand, eliminating over-provisioning
Aurora Serverless v2 scales compute in fine-grained increments (0.5 ACU) almost instantly, so you pay only for the capacity used rather than provisioning for peak load.
Question 2: An architect needs to analyze AWS spending patterns and forecast future costs. Which AWS tool provides this capability?
- AWS Budgets
- AWS Cost Explorer (Correct answer)
- AWS Pricing Calculator
- AWS Trusted Advisor
Correct answer: AWS Cost Explorer
AWS Cost Explorer provides an interactive interface to visualize, understand, and forecast your AWS costs and usage over time with up to 12 months of historical data.
Question 3: Which S3 feature automatically transitions objects to cheaper storage classes based on their age, reducing long-term storage costs?
- S3 Object Lock
- S3 Lifecycle Policies (Correct answer)
- S3 Replication
- S3 Intelligent-Tiering
Correct answer: S3 Lifecycle Policies
S3 Lifecycle Policies define rules that automatically transition objects to lower-cost storage classes (e.g., Standard → IA → Glacier) or expire them based on object age.
Question 4: What is the advantage of using AWS Lambda over EC2 for event-driven, short-duration tasks from a cost optimization perspective?
- Lambda uses cheaper hardware than EC2
- Lambda bills in 1ms increments with no charge when idle, unlike EC2 which accrues cost while running (Correct answer)
- Lambda has free unlimited storage
- Lambda instances are reserved and always cheaper
Correct answer: Lambda bills in 1ms increments with no charge when idle, unlike EC2 which accrues cost while running
Lambda charges only for the compute time consumed during function execution (rounded to 1 ms), whereas EC2 charges per second/hour regardless of whether the instance is actively processing requests.
Question 5: Which AWS service provides recommendations to help you follow AWS best practices for cost, security, fault tolerance, and performance?
- AWS Config
- AWS Systems Manager
- AWS Trusted Advisor (Correct answer)
- AWS Well-Architected Tool
Correct answer: AWS Trusted Advisor
AWS Trusted Advisor inspects your AWS environment and provides real-time guidance to provision resources following AWS best practices across five categories.
Question 6: An architect wants to reduce NAT Gateway data processing costs. Which design change could help for traffic that stays within AWS?
- Use S3 Transfer Acceleration instead
- Use VPC Gateway Endpoints for S3 and DynamoDB to bypass NAT Gateway (Correct answer)
- Enable VPC Flow Logs to identify top consumers
- Switch to an Internet Gateway
Correct answer: Use VPC Gateway Endpoints for S3 and DynamoDB to bypass NAT Gateway
VPC Gateway Endpoints route traffic to S3 and DynamoDB directly through the AWS network without traversing a NAT Gateway, eliminating NAT data processing charges for those services.
Architecting on AWS Certification Architecting on AWS Certification Cost Optimization & Performance Efficiency 2
What is the primary benefit of using Amazon Aurora Serverless v2 compared to a provisioned Aurora cluster for a variable-workload application?