Load balancing is a process used to distribute network or application traffic across multiple servers, ensuring no single server becomes overwhelmed. Improving responsiveness and availability of applications, websites, and databases. Helping in resource optimization, maximizing throughput, minimizing response time, and avoiding overload of any single resource.
Algorithms used in load balancing:
- Round Robin
This is the simplest and most commonly used balancing algorithm, distributing client request sequentially across a group of servers. Best suited for servers with similar capacities and when client requests are consistent and uniform.
- Weighted Round Robin
Similar to Round Robin, but allows assigning a weight to each server based on its capacity. Servers with higher weights receive more requests. Useful when servers have different processing capabilities.
- Least Connections
It directs traffic to the server with the fewest active connections. Assuring that servers handling fewer connections will likely be able to process new requests more quickly. Effective in environments where the load varies significantly and servers have different capabilities.
- Least Response Time
Sends requests to the server with the fastest response time and the fewest active connections. Ideal for applications where response time is critical and varies greatly between servers.
- Source IP Hash
Uses the client’s IP address to generate a unique hash key. This key determines which server will handle the request, ensuring the same client always connects to the same server. Useful for session persistence, ensuring a user’s session remains on the same server throughout.
- URL Hash
Creates a hash of the requested URL to determine the server. This ensures requests for the same URL are directed to the same server, enhancing caching performance. Useful for applications with significant caching needs.
- Least bandwidth
Routes traffic to the server that is currently saving the least amount of traffic by bandwidth. Useful in scenarios where servers have varied bandwidth capacities.
- Random
Distributes client request to servers randomly. This algorithm is simple but does not ensure even distribution of load. Used for testing purposes or in very small, low-traffic environments.
Some benefits of load balancing include improved availability and reliability, ensuring that no SPOF (Single Point of Failure) can take down the service, scalability, redundancy and efficiency.
