What is a single point of failure and how do you eliminate it?

A Single Point of Failure (SPOF) is any component whose failure would cause the entire system to fail. Common SPOFs include:

• Hardware: Single server, network switch, power supply
• Software: Single database instance, application server
• Network: Single internet connection, DNS server
• Human: Single administrator with exclusive knowledge

Elimination strategies:

• Redundancy: Multiple instances of critical components
• Load Balancing: Distribute traffic across multiple nodes
• Clustering: Group servers to act as one logical unit
• Geographic Distribution: Multiple data centers
• Documentation: Ensure knowledge is shared among team members

Example: Instead of one web server, deploy three servers behind a load balancer with health checks.