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Concept: Understanding High Availability and Failover with Load Balancers

Overview

High Availability (HA) ensures that systems remain accessible even when individual components fail.
Load balancers are a key part of HA strategies, distributing traffic across multiple servers and handling failover.

Audience: IT professionals, support engineers, developers
Skill Level: Beginner–Intermediate

Key Concepts

  • High Availability (HA): Designing systems to minimize downtime.
  • Failover: Automatic redirection of traffic when a server becomes unavailable.
  • Load Balancer: A device or software that distributes traffic among servers.

How Failover Works

  1. Health checks detect an unhealthy server
  2. Load balancer removes the server from rotation
  3. Traffic is routed to healthy servers
  4. Failed server is restored and re-added

Example Diagram

  • Insert a simple diagram later showing clients → load balancer → servers

Best Practices

  • Use multiple load balancer nodes (active-passive or active-active).
  • Monitor system health regularly.
  • Test failover scenarios before production use.

References