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

SPOF is any component whose failure would bring down the entire system. Elimination strategies: redundancy (multiple instances), load balancing (distribute across instances), failover (automatic switch to backup), geographic distribution. Common SPOFs: single database server, single load balancer, single DNS provider, single region. Design for no single points: redundant everything critical, health checks, automatic failover. Cloud providers help with managed services. Accept some SPOF for non-critical components based on cost.