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Load Balancer

1️⃣ What is a Load Balancer?​

A Load Balancer is a system that distributes incoming network traffic across multiple servers to ensure:

  • High availability
  • Performance optimization
  • Reliability and fault tolerance

Analogy:​

Imagine a traffic officer directing cars to different lanes to prevent congestion and ensure smooth flow. 🚦

2️⃣ Why Do We Need a Load Balancer?​

🔹 High Availability: Ensures application uptime even if some servers fail
🔹 Scalability: Handles increased traffic efficiently
🔹 Better Performance: Prevents server overload and reduces response times
🔹 Redundancy & Failover: Automatically redirects traffic if a server goes down

3️⃣ How Does a Load Balancer Work?​

1️⃣ A user makes a request (e.g., visiting a website) 🌍
2️⃣ The request reaches the Load Balancer 🔄
3️⃣ The Load Balancer selects an available server based on an algorithm 🎯
4️⃣ The server processes the request and sends a response 🔁
5️⃣ The Load Balancer ensures equal distribution of traffic ⚡

4️⃣ Types of Load Balancers​

1. Hardware Load Balancer​

✅ Dedicated physical device
✅ High performance, but expensive 💰

2. Software Load Balancer​

✅ Runs on standard hardware
✅ Cost-effective and flexible ⚡

3. Cloud-Based Load Balancer​

✅ Managed by cloud providers (AWS, Azure, GCP)
✅ Scales dynamically based on traffic 📈

5️⃣ Load Balancing Algorithms​

📌 How does a Load Balancer decide which server gets the request?

1️⃣ Round Robin: Sends requests to each server in order 🔄
2️⃣ Least Connections: Chooses the server with the fewest active connections 🔗
3️⃣ IP Hash: Routes requests based on the client’s IP address 🌍
4️⃣ Weighted Load Balancing: Prioritizes more powerful servers ⚖️

6️⃣ Load Balancer in Real-World Applications​

📌 Common Use Cases:
✅ Web Applications – Preventing downtime and improving user experience 🌐
✅ E-commerce Sites – Handling high traffic on sales days 🛒
✅ Streaming Services – Preventing buffering in video streaming 🎥
✅ Online Gaming – Managing thousands of concurrent players 🎮

Cloud-Based:​

  • ✅ AWS Elastic Load Balancer (ELB)
  • ✅ Google Cloud Load Balancer
  • ✅ Azure Load Balancer

Software-Based:​

  • ✅ Nginx
  • ✅ HAProxy
  • ✅ Traefik

8️⃣ Summary​

✅ A Load Balancer distributes traffic among multiple servers
✅ Improves availability, scalability, and reliability
✅ Uses different algorithms to optimize performance
✅ Essential for handling high traffic & preventing downtime

Would you like additional details or a diagram to complement these notes? 🚀