System Architect - Expert Guide

Design robust, scalable systems that power global applications and handle extreme scale.

🎯 Expert Coverage

System Design Fundamentals

Design Process

• Requirements clarification
• Back-of-envelope estimations
• Capacity planning
• Bottleneck analysis
• Trade-off evaluation
• Technology selection

Scalability Concepts

• Vertical scaling limitations
• Horizontal scaling patterns
• Database replication
• Sharding strategies
• Caching layers
• Load balancing algorithms
• Content delivery networks (CDN)

Architecture Styles

Monolithic Architecture

• Single deployable unit
• Database per application
• Simpler deployment
• Tight coupling challenges

Microservices Architecture

• Independent services
• API-first communication
• Polyglot persistence
• Service mesh integration
• Distributed transactions (Saga pattern)
• Service discovery and registration

Event-Driven Architecture

• Event sourcing
• CQRS (Command Query)
• Message brokers (Kafka, RabbitMQ)
• Event streaming
• Eventual consistency

Serverless Architecture

• Function-as-a-service
• Auto-scaling benefits
• Cold start challenges
• Vendor lock-in trade-offs

Database Architecture

Data Store Selection

• OLTP vs OLAP databases
• SQL vs NoSQL decision matrix
• In-memory databases
• Graph databases
• Search engines (Elasticsearch)

Scalability Patterns

• Read replicas
• Sharding by key ranges
• Directory-based sharding
• Replication strategies
• Backup and recovery

Caching Strategies

Caching Layers

• Client-side caching
• CDN caching
• Application caching
• Database caching
• Cache invalidation strategies

Cache Patterns

• Cache-aside (lazy loading)
• Write-through
• Write-behind
• Time-to-live (TTL)
• Distributed caching

API Design

REST APIs

• Resource-oriented design
• HTTP semantics
• Pagination strategies
• API versioning
• Error handling
• Rate limiting

GraphQL

• Schema design
• Query optimization
• N+1 problem mitigation
• Subscription handling

gRPC

• Protocol Buffers
• Streaming communication
• Performance advantages
• Load balancing

Reliability & Resilience

Failure Handling

• Circuit breaker pattern
• Retry strategies with exponential backoff
• Bulkhead pattern
• Timeout management
• Graceful degradation

High Availability

• Redundancy elimination
• Failover mechanisms
• Health checks
• Load balancing
• Multi-region deployment

Monitoring & Observability

Metrics

• Application metrics (latency, throughput, errors)
• System metrics (CPU, memory, disk, network)
• Business metrics
• SLI/SLO definition
• Custom instrumentation

Logging & Tracing

• Structured logging
• Log aggregation
• Distributed tracing
• Request correlation
• Performance profiling

Cost Optimization

Resource Optimization

• Right-sizing instances
• Reserved vs on-demand
• Spot instances
• Auto-scaling policies
• Database optimization

Architectural Cost

• Data transfer costs
• API call optimization
• Storage compression
• Caching efficiency
• Cost monitoring

Security Architecture

Defense in Depth

• Network security (VPC, security groups)
• API authentication (OAuth, mTLS)
• Encryption (in-transit, at-rest)
• Secrets management
• DDoS protection

Compliance

• Data residency
• Audit logging
• Access control
• Data privacy (GDPR, CCPA)

📚 Learning Path (12 Weeks)

Weeks 1-2: Foundations

• Scalability concepts
• Load testing
• Capacity planning
• Back-of-envelope math

Weeks 3-4: Core Patterns

• Caching strategies
• Database replication
• API design
• Load balancing

Weeks 5-7: Advanced Architecture

• Microservices design
• Event-driven systems
• Distributed transactions
• Service mesh

Weeks 8-9: Real-World Examples

• Twitter-scale design
• YouTube-scale design
• Uber system design
• Netflix architecture

Weeks 10-12: Production Systems

• Cost optimization
• Security architecture
• Monitoring setup
• Case study analysis

🛠️ Technology Stack

Load Balancing: Nginx, HAProxy, AWS ELB, Google Load Balancer Caching: Redis, Memcached, Varnish, CDN (CloudFlare, Akamai) Databases: PostgreSQL, MongoDB, Cassandra, DynamoDB Message Brokers: Kafka, RabbitMQ, AWS SQS, Google Pub/Sub Monitoring: Prometheus, Grafana, DataDog, New Relic Tracing: Jaeger, Zipkin, AWS X-Ray Service Mesh: Istio, Linkerd, Consul Container Orchestration: Kubernetes, Docker Swarm

🎯 Interview Preparation

Estimation Skills

• QPS (queries per second) calculation
• Storage requirements
• Bandwidth calculation
• Latency analysis

Design Patterns

• Consistent hashing
• Bloom filters
• Rate limiting algorithms
• Consensus algorithms

Real-World Case Studies

• Facebook messenger
• Instagram feed
• Spotify playlist
• Airbnb booking system

💼 Career Path

Level	Experience	Role	Salary
Senior Engineer	5-8 years	Technical Lead	$150K-$250K
Staff Engineer	8-12 years	Architecture	$250K-$400K+
Principal Engineer	12+ years	Strategy	$400K-$700K+

🚀 When to Invoke

• Large-scale system design
• Scalability analysis
• Database architecture
• Microservices planning
• Technology evaluation
• Performance optimization
• Cost optimization
• Reliability improvements
• Security hardening
• Trade-off analysis