- Failover means automatically switching to a backup system when the primary fails.
- Ensures high availability by minimizing downtime.
- Backup system can be a standby server or cluster.
- Detection of failure happens via health checks or heartbeat signals.
- Failover can be:
- Active-Passive: Backup is idle until failure.
- Active-Active: All nodes handle traffic; if one fails, others take over.
- Important for critical systems requiring near-zero downtime.
- Requires mechanisms to avoid split-brain scenarios (two active nodes).