Ruigu Electronic

Prevent Single-Point Overload: Avoid bottlenecks caused by unevenly distributed traffic on a single server.
Enhance System Availability: If one server fails, traffic is automatically redirected to healthy nodes, reducing downtime.
Optimize Resource Utilization: Ensure all servers in a cluster operate at a balanced load level.
Improve Response Time: Minimize latency by routing requests to the closest or least busy server.

Hardware Load Balancers
- Dedicated physical devices designed for high-performance traffic distribution (e.g., F5 BIG-IP, Citrix ADC).
- Advantages: High throughput, low latency, strong security features (e.g., DDoS protection).
- Disadvantages: High cost, complex maintenance, limited scalability.
Software Load Balancers
- Deployed as software applications or modules on general-purpose servers (e.g., Nginx, HAProxy, Apache HTTP Server with mod_proxy_balancer).
- Advantages: Low cost, flexible deployment, easy scalability, suitable for cloud and container environments.
- Disadvantages: Performance is constrained by the underlying server hardware.
Cloud Load Balancers
- Managed services provided by cloud providers (e.g., AWS Elastic Load Balancing (ELB), Azure Load Balancer, Google Cloud Load Balancing).
- Advantages: Fully managed, pay-as-you-go, auto-scaling, seamless integration with cloud resources.

The algorithm determines how traffic is distributed across backend resources. Key algorithms include:

Algorithm	Description	Use Case
Round Robin	Distributes requests sequentially to each server in turn.	Uniformly configured servers with similar performance.
Weighted Round Robin	Assigns weights to servers; higher-weight servers receive more requests.	Servers with different hardware configurations (e.g., high-performance servers get higher weights).
Least Connections	Routes new requests to the server with the fewest active connections.	Applications with long-lived connections (e.g., database connections, VoIP).
Weighted Least Connections	Combines weight settings with the least-connections logic.	Mixed server clusters with varying performance and connection loads.
IP Hash	Uses the client’s IP address to calculate a hash value and map it to a specific server. Ensures a client’s requests are always sent to the same server (session persistence).	Applications requiring session continuity (e.g., e-commerce shopping carts).
Least Response Time	Selects the server with the fewest active connections and the shortest average response time.	High-demand applications sensitive to latency.