Load Balancing Algorithms

Choosing the Right Algorithm:

1. Round Robin: Distributes incoming requests sequentially across a list of servers. Each server receives an equal share of requests in a rotating order.

   • Uniform Workload: When the servers have similar capabilities and the incoming requests are relatively uniform in processing time and resource usage.
   • Simple and Effective: For simple and straightforward distribution without specific optimization needs.

2. Least Connections: Directs traffic to the server with the fewest active connections at the time the request is received.

   • Variable Load: When incoming requests have varying levels of complexity and processing times.
   • Optimal Utilization: Helps in environments where some requests may take longer to process, ensuring that no single server gets overloaded.

3. Least Response Time: Sends requests to the server with the fastest response time and least number of active connections.

4. IP Hash: Uses a hash of the client’s IP address to determine which server will handle the request.

   • Session Persistence: When it’s important that requests from the same client are consistently directed to the same server, such as in stateful applications.
   • Consistency: Useful for applications where maintaining state between client and server is crucial.

5. Weighted Round Robin: Similar to Round Robin, but allows assigning different weights to servers based on their capacity. Servers with higher weights receive more requests.

   • Heterogeneous Server Environments: When servers have different processing capabilities or resources.
   • Optimized Resource Utilization: Ensures that more powerful servers handle a larger share of the load.

6. Weighted Least Connections: Combines the principles of Least Connections and Weighted Round Robin. Requests are sent to servers based on their weights and current load.

7. Random: Distributes requests to servers randomly. and efficient systems during interviews.

   • Simplicity: For basic load balancing needs where advanced algorithms are not required.
   • Uniform Load Distribution: Useful in environments with uniformly distributed and predictable workloads.