π System Design Index
System design patterns and architecture concepts essential for building scalable, reliable, and maintainable distributed systems.
Overview
System design is the process of defining the architecture, components, modules, interfaces, and data for a system to satisfy specified requirements. This section covers fundamental patterns and concepts used in modern distributed systems.
Core Concepts
Load Balancing
- 1 Load Balancing Algorithms - Round robin, least connections, and other algorithms
Communication Patterns
- 2 Inter-Process Communication (IPC) - Methods for processes to communicate
Authentication
- 3 Single Sign-On (SSO) - Centralized authentication across multiple systems
Resources
- 4 System Design Resources - Learning materials and references
Learning Path
Follow this sequence for optimal understanding:
- Load Balancing: 1 Load Balancing Algorithms - Understand traffic distribution
- Communication: 2 Inter-Process Communication (IPC) - Learn process communication
- Authentication: 3 Single Sign-On (SSO) - Master centralized auth
- Resources: 4 System Design Resources - Explore additional materials
Key Concepts
Scalability Patterns
Horizontal Scaling
- Add more machines to handle load
- Requires load balancing
- Better fault tolerance
- More complex to implement
Vertical Scaling
- Add more resources to existing machine
- Simpler to implement
- Hardware limitations
- Single point of failure
Caching
- Reduce database load
- Improve response times
- Cache invalidation challenges
- Multiple caching layers
Database Sharding
- Partition data across multiple databases
- Improve query performance
- Complex to implement
- Rebalancing challenges
Reliability Patterns
Redundancy
- Eliminate single points of failure
- Active-active or active-passive
- Data replication
- Geographic distribution
Health Checks
- Monitor service availability
- Automatic failover
- Circuit breakers
- Graceful degradation
Retry Logic
- Handle transient failures
- Exponential backoff
- Idempotency considerations
- Maximum retry limits
Rate Limiting
- Prevent system overload
- Protect against abuse
- Fair resource allocation
- Multiple rate limit tiers
Communication Patterns
Synchronous
- Request-response model
- HTTP/REST APIs
- gRPC
- Direct coupling
Asynchronous
- Message queues
- Event-driven architecture
- Pub/sub patterns
- Loose coupling
Service Mesh
- Service-to-service communication
- Load balancing and discovery
- Security and observability
- Traffic management
Data Patterns
Database Types
- Relational (SQL) - ACID transactions
- NoSQL - Flexible schema, horizontal scaling
- Key-Value - Simple, fast lookups
- Document - JSON-like documents
- Graph - Relationship-focused
Data Consistency
- Strong consistency - Always up-to-date
- Eventual consistency - Eventually up-to-date
- CAP theorem - Consistency, Availability, Partition tolerance
Data Replication
- Master-slave replication
- Multi-master replication
- Read replicas
- Cross-region replication
AWS System Design Components
Compute
- EC2 - Virtual machines
- ECS - Container orchestration
- Step Functions - Workflow orchestration
Load Balancing
Networking
- VPC - Network isolation
- Security Groups - Firewall rules
- Reverse Proxy - Traffic routing
Data Streaming
- Kinesis - Real-time data streaming
Infrastructure
- CloudFormation - Infrastructure as Code
- IaaC - IaC concepts
Security
- Secrets Manager - Secrets management
- IAM - Access control
Design Principles
Scalability
- Design for horizontal scaling
- Use stateless services when possible
- Implement caching strategically
- Partition data effectively
Reliability
- Eliminate single points of failure
- Implement health checks and monitoring
- Use multiple availability zones
- Plan for disaster recovery
Performance
- Optimize database queries
- Use CDNs for static content
- Implement efficient caching
- Choose appropriate data structures
Security
- Defense in depth
- Principle of least privilege
- Encrypt data in transit and at rest
- Regular security audits
Cost Optimization
- Right-size resources
- Use auto scaling
- Leverage spot instances
- Monitor and optimize continuously
Maintainability
- Clear documentation
- Consistent naming conventions
- Modular architecture
- Automated testing
Common Architecture Patterns
Microservices
- Small, independent services
- Each service owns its data
- Communicate via APIs
- Independent deployment
Event-Driven
- Services react to events
- Loose coupling
- Asynchronous processing
- Scalable and resilient
Serverless
- No server management
- Pay per execution
- Auto-scaling
- Event-driven
Monolithic
- Single deployable unit
- Simpler to develop initially
- Tighter coupling
- Harder to scale
System Design Interview Topics
Common Questions
- Design a URL shortener
- Design a social media feed
- Design a distributed cache
- Design a rate limiter
- Design a notification system
- Design a chat application
- Design a file storage system
- Design a search engine
Approach
- Clarify requirements - Functional and non-functional
- Estimate scale - Users, requests, storage
- High-level design - Major components
- Deep dive - Detailed component design
- Identify bottlenecks - Performance, scalability
- Discuss trade-offs - Different approaches
Related Topics
Prerequisites
- Internet Fundamentals - Networking basics
- VPC - AWS networking
AWS Services
- EC2 - Compute foundation
- ECS - Container orchestration
- AWS Services - Additional services
Implementation
Learning Resources
Books
- Designing Data-Intensive Applications (Martin Kleppmann)
- System Design Interview (Alex Xu)
- Building Microservices (Sam Newman)
- Site Reliability Engineering (Google)
Online Resources
- ByteByteGo - System design content
- System Design Primer (GitHub)
- AWS Architecture Center
- High Scalability blog
Practice
- Design real-world systems
- Review architecture of popular services
- Participate in system design discussions
- Build and deploy distributed systems