What is Failover?
Failover is the automatic process of switching to a redundant or standby server, system, or network when the primary one fails, ensuring continuous service availability with minimal interruption.
How Does Failover Work?
Failover mechanisms continuously monitor the health of primary systems and are designed to detect failures within seconds. When a failure is detected, traffic is automatically redirected to a backup system that takes over the workload. This can occur at multiple levels including server hardware, network connections, storage systems, and even entire data centers in the case of geographic failover.
Effective failover requires careful planning, including maintaining synchronized data between primary and backup systems, regular testing of failover procedures, and monitoring to ensure the backup system is always ready. The time it takes to complete a failover, known as recovery time, varies from near-instantaneous with active-active configurations to several minutes with cold standby setups.