Load balancing can be implemented at various layers of the OSI model, including Layer 4 (Transport) and Layer 7 (Application). Layer 4 load balancers route traffic based on IP address and TCP/UDP protocols, while Layer 7 load balancers can make routing decisions based on the content of the request (e.g., URL, HTTP headers). Choosing the right strategy depends on the application requirements and traffic patterns.
Common load balancing algorithms include round-robin, least connections, and IP hash. Round-robin distributes requests evenly, least connections directs traffic to the server with the fewest active connections, and IP hash ensures that requests from the same client go to the same server. Each has trade-offs in terms of complexity, efficiency, and suitability for different workloads.
- Improved availability through redundancy.
- Enhanced performance by distributing load.
- Scalability to handle increased traffic.
Common pitfalls include improper configuration of health checks, which can lead to traffic being directed to unresponsive servers, and not accounting for session persistence when required, which can disrupt user experiences.