AWS SAA Mock Exam 3 - Cost Optimization & Performance

📝 Exam Information

  • Focus Areas: Cost Optimization, Performance Efficiency
  • Duration: 130 minutes
  • Questions: 65 questions
  • Difficulty: Intermediate to Advanced

Question 1

A company runs a web application that experiences predictable traffic patterns: high usage 9 AM - 6 PM weekdays, minimal usage evenings và weekends. Current setup uses 10 m5.large instances running 24/7. How can costs be optimized while maintaining performance?

A) Use Spot Instances với Auto Scaling groups B) Use Reserved Instances + Scheduled Scaling C) Migrate to Lambda Serverless architecture
D) Use smaller instance types với more instances

Answer: B Explanation: Reserved Instances provide cost savings cho predictable base load, Scheduled Scaling adjusts capacity based on known traffic patterns.

Question 2

An e-commerce application's RDS database experiences high read traffic during shopping events. Read queries are causing performance issues for write operations. Which solution provides the BEST performance improvement at lowest cost?

A) Upgrade to larger RDS instance class B) Enable Multi-AZ deployment với read replicas C) Create read replicas và route read traffic to them D) Use DynamoDB với DynamoDB Accelerator (DAX)

Answer: C Explanation: Read replicas offload read traffic from primary database, improving write performance without expensive instance upgrades.

Question 3

A data processing application uploads 1 TB của files daily to S3, processes them within 24 hours, then rarely accesses them. Files must be retained for compliance for 7 years. Which storage strategy minimizes costs?

A) S3 Standard → S3 IA (30 days) → Glacier (90 days) → Deep Archive (1 year) B) S3 Standard (1 day) → S3 IA (30 days) → Glacier Instant Retrieval (90 days) C) S3 Intelligent-Tiering với automatic archiving D) S3 One Zone-IA → Glacier Deep Archive (90 days)

Answer: A Explanation: Progressive lifecycle transitions minimize storage costs while maintaining appropriate access tiers cho different retention periods.

Question 4

A Lambda function processes S3 events but occasionally times out after 15 minutes when processing large files. The function requires 2 GB memory để process files efficiently. Which solution optimizes both performance và cost?

A) Increase Lambda timeout to maximum 15 minutes B) Split processing into smaller Lambda functions với Step Functions C) Increase memory to 3 GB để reduce processing time D) Use ECS Fargate với spot pricing for long-running tasks

Answer: D Explanation: ECS Fargate với spot pricing cost-effective cho long-running tasks, Lambda has 15-minute limit và costs more for extended processing.

Question 5

A company uses CloudFront to distribute content globally. Analytics show 80% của requests come from 3 regions, but content is cached at all edge locations. How can costs be optimized?

A) Use CloudFront Price Class 100 (North America, Europe) B) Use CloudFront Price Class 200 (North America, Europe, Asia)
C) Implement geo-blocking for unused regions D) Use S3 Transfer Acceleration instead của CloudFront

Answer: B Explanation: Price Class 200 covers major regions where 80% của traffic originates, reducing costs while maintaining performance for primary users.

Question 6

An application requires a database with microsecond latency for session storage và can tolerate some data loss. Current DynamoDB setup with strong consistency is expensive. Which optimization reduces costs?

A) Use ElastiCache Redis với clustering B) Switch to DynamoDB eventually consistent reads C) Use DynamoDB on-demand pricing mode D) Implement application-level caching

Answer: A Explanation: ElastiCache Redis provides microsecond latency at lower cost than DynamoDB for session storage, tolerates data loss with proper design.

Question 7

A batch processing job runs monthly for 48 hours, processing financial reports. Current setup uses 20 m5.xlarge On-Demand instances. Which approach minimizes costs?

A) Use Spot Instances với automatic bidding B) Purchase Reserved Instances cho the instances C) Use Scheduled Reserved Instances D) Migrate to AWS Batch với Spot Fleet

Answer: D Explanation: AWS Batch với Spot Fleet optimal cho infrequent, fault-tolerant batch workloads, provides significant cost savings over On-Demand.

Question 8

A video transcoding service processes uploaded videos using FFmpeg. Processing times vary from 5 minutes to 2 hours. Current Lambda functions timeout frequently. Which architecture optimizes cost và performance?

A) Use Step Functions với multiple Lambda functions B) Use ECS Fargate với auto-scaling based on queue depth C) Use EC2 Spot Instances với SQS queue D) Use AWS Elemental MediaConvert service

Answer: D Explanation: MediaConvert is purpose-built cho video processing, more cost-effective than compute resources cho video transcoding workloads.

Question 9

A multi-tier application uses ALB, EC2 instances, và RDS. Traffic analysis shows 60% của database queries are repetitive reads. Which caching strategy provides best performance improvement?

A) Enable RDS query cache B) Implement ElastiCache between application và database C) Use CloudFront để cache database responses D) Enable DynamoDB Accelerator (DAX)

Answer: B Explanation: ElastiCache between application và RDS reduces database load, improves response times cho repetitive queries.

Question 10

A company stores 500 TB của infrequently accessed data in S3 Standard. Data is accessed once every 3-4 months for auditing. Retrieval time của up to 12 hours is acceptable. Which storage class minimizes costs?

A) S3 Standard-IA B) S3 Glacier Instant Retrieval C) S3 Glacier Flexible Retrieval D) S3 Glacier Deep Archive

Answer: D Explanation: Deep Archive provides lowest cost cho rarely accessed data (3-4 times/year), 12-hour retrieval time is acceptable.

Question 11-30

[Additional performance and cost optimization questions covering:] - Auto Scaling strategies - Reserved Instance optimization - Storage lifecycle policies - Database performance tuning - Network optimization - Serverless cost optimization

Domain Breakdown

Cost Optimization (40%)

  • Reserved Instances vs Spot vs On-Demand
  • Storage lifecycle management
  • Right-sizing recommendations
  • Pricing models comparison

Performance Efficiency (35%)

  • Caching strategies
  • Database optimization
  • Network performance
  • Compute optimization

Reliability (15%)

  • Auto Scaling configurations
  • Disaster recovery cost optimization
  • Multi-AZ cost considerations

Security (10%)

  • Cost-effective security solutions
  • Encryption performance impact

Key Performance Metrics

  • Cost per transaction
  • Response time optimization
  • Throughput maximization
  • Resource utilization

Study Recommendations

  1. Practice cost calculations cho different scenarios
  2. Understand pricing models cho all major services
  3. Learn performance optimization techniques
  4. Study cost monitoring tools (Cost Explorer, Budgets)
  5. Review Well-Architected Framework cost optimization pillar