System Design Essentials

Read this article and found to be quite interesting dropped my notes on what I took away from it:

System Design Essentials: The Big 5 | by Vedant Raut | Javarevisited | Apr, 2025 | Medium

Summary

The article discusses five fundamental concepts essential for mastering system design interviews and building scalable systems:

1. Load Balancing

   • Distributes traffic across multiple servers to prevent overload.

   • Common algorithms: Round Robin, Least Connections, IP Hashing.

   • Tools: Nginx, HAProxy, AWS ELB.

2. Caching

   • Reduces latency and database load by storing frequently accessed data.

   • Types:

     • In-memory (Redis, Memcached) for fast access.

     • CDN caching for static content.

   • Cache Eviction Policies: LRU (Least Recently Used), FIFO, LFU.

3. Database Scaling

   • Vertical Scaling: Upgrading server capacity (CPU, RAM).

   • Horizontal Scaling: Adding more servers (sharding, partitioning).

   • Replication: Master-slave setup for read-heavy workloads.

4. Microservices Architecture

   • Breaks monolithic apps into smaller, independent services.

   • Pros: Scalability, fault isolation, tech flexibility.

   • Cons: Complexity in management, network latency.

5. Message Queues (Pub/Sub & Queues)

   • Decouples services for asynchronous processing.

   • Use Cases: Order processing, notifications, logs.

   • Tools: Kafka, RabbitMQ, AWS SQS.

Key Takeaways (Important Notes)

✅ Scalability depends on load balancing, caching, and database optimization.
✅ Caching is crucial for high-performance systems (choose the right eviction policy).
✅ Microservices improve flexibility but require strong DevOps practices.
✅ Message queues ensure reliability in distributed systems.
✅ Always consider trade-offs (e.g., consistency vs. availability in CAP theorem).