A load balancer can be a device or software that distributes incoming network traffic across multiple servers to improve performance, reliability, and scalability. It acts as a traffic manager, ensuring that workload is evenly distributed among available servers, preventing any single server from becoming overloaded.
Key functions of a load balancer:
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Traffic distribution: It directs incoming traffic to the most appropriate server based on various factors, such as server load, health status, and application requirements.
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Failover: If a server fails or becomes unresponsive, the load balancer can automatically redirect traffic to a working server, ensuring uninterrupted service.
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Session persistence: It can maintain session affinity, ensuring that requests from a particular client are always routed to the same server, preserving the state of the session.
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Performance optimization: Load balancers can improve performance by reducing latency, increasing throughput, and enhancing overall system responsiveness.
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Security: Some load balancers can provide security features like SSL termination, DDoS protection, and access control.
Example:
In an e-commerce website, a load balancer can distribute incoming traffic from customers across multiple web servers, ensuring that the website remains responsive even during peak traffic periods. If one server fails, the load balancer can automatically redirect traffic to another server, preventing service interruptions.