Definition, synonyms and related words
An automatic switch to a secondary system on failure of the primary system, such as a means for ensuring high availability of some critical resource (such as a computer system), involving a parallel backup system which is kept running at all times so that, upon detected failure of the primary system, processing can be automatically shifted over to the backup.
"The server's failover mechanism instantly routed our transactions to the standby database when the main unit crashed during peak traffic hours."