System Design Fundamentals

System design connects business requirements to measurable guarantees, capacity constraints, and failure behavior. These fundamentals provide the basis for comparing architecture options.

Core topics

• Requirements and constraints
• Functional vs non-functional requirements
• Scalability
• Latency
• Throughput
• Concurrency
• Availability
• Reliability
• Durability
• Consistency
• CAP
• PACELC
• Timeouts
• Retries
• Backoff and jitter
• Circuit breakers
• Bulkheads
• Rate limiting
• Backpressure
• Graceful degradation

Architecture concepts

• Requirements & Constraints
• Scalability, Latency & Throughput
• Availability & Reliability
• Consistency Models

Reliability & Resilience covers failure handling and recovery concerns that cut across these decisions.