Day 22: Working on a Full System Design Project
1. Understanding System Design Basics:
Before you begin designing a full system, it's crucial to understand the core principles behind scalable and maintainable system design. Focus on:
Scalability: How the system can handle increased traffic or data.
Availability: Ensuring minimal downtime, even under high load.
Consistency vs. Latency: Trade-offs between strong consistency (e.g., accurate data retrieval) and low latency (e.g., fast response times).
Fault Tolerance: Designing for failure recovery and redundancy.
Load Balancing: Distributing user requests across multiple servers.
2. Requirements Gathering:
Define the functional requirements of the system (e.g., user registration, posting, commenting, liking, and sharing content).
Define non-functional requirements like performance (response time < 100ms), scalability (able to handle millions of users), and availability (99.9% uptime).
Example for a social media platform:
Core features: User profiles, news feed, content creation, notifications, and real-time messaging.
Advanced features: Recommendations, trending topics, and search functionality.
3. System Components:
Break down the system into smaller, manageable components. A typical social media platform consists of:
Client-Side (Frontend): Web/mobile app interfaces where users interact with the platform.
Backend Services:
User Service: Manages user data (registration, login, profiles).
Post Service: Manages creation and retrieval of user posts, comments, etc.
Feed Service: Provides relevant content in the user’s feed (friends' posts, likes, etc.).
Notification Service: Pushes updates to users when something happens (e.g., when someone likes their post).
Messaging Service: Manages real-time or asynchronous messaging between users.
4. Database Design:
Choose a database strategy depending on use cases:
Relational Databases (SQL): Use if data integrity and relationships are important (e.g., friends, followers).
NoSQL Databases: For handling high-velocity, unstructured data (e.g., posts, comments).
Caching Layer: To reduce database load and improve performance (e.g., use Redis or Memcached for storing frequently accessed data like user session information).
Example schema for social media:
User Table: Stores user information (ID, name, email, etc.).
Post Table: Contains posts (ID, userID, content, timestamp, etc.).
Comments Table: Linked to posts with postID.
Likes Table: Stores likes for posts with userID, postID.
5. High-Level Design Diagram:
Visualize your system design with a high-level diagram:
Client → API Gateway → Backend Services → Database → Caching Layer.
Add load balancers to distribute requests across servers.
Include a Content Delivery Network (CDN) for serving static assets (images, videos).
6. Key Design Considerations:
Data Sharding: For large-scale databases, consider sharding (horizontal partitioning) to distribute data across servers.
Content Delivery Networks (CDN): Use CDN for faster delivery of media files (images, videos).
Data Replication & Backup: Ensure redundancy and backup in case of server failures.
Security: Implement OAuth for user authentication, encrypt sensitive data, and set up firewalls for security.
7. Handling Scale:
Load Balancing: Distribute traffic across multiple servers (e.g., Nginx or AWS Elastic Load Balancer).
Microservices Architecture: Break down your monolithic application into smaller, independent services.
Database Partitioning: Use database partitioning techniques (e.g., range-based or hash-based partitioning) to handle large datasets.
8. System Design Best Practices:
Design for Failure: Assume components will fail. Implement mechanisms for fault tolerance (e.g., retry logic, failover systems).
Horizontal Scaling: Add more servers to handle increased load (versus vertical scaling which adds more power to a single server).
Monitoring & Logging: Set up logging (e.g., ELK stack) and monitoring tools (e.g., Prometheus, Grafana) to keep track of system health.
Next Steps:
Create a high-level design: Based on these notes, sketch out your design diagram.
Focus on one key feature at a time: Implementing user profiles and post services first.
Document your assumptions: Clarify how you intend to handle scalability, availability, and data consistency.
For Day 22, your goal is to develop the first iteration of the system design with a focus on covering the essential services and components. You can refine the design and add more details in the next few days.
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