High-availability applications can be categorized to different modes in a cluster,
- hot standby
- warm standby
- cold standby
Hot standby—Applications on the backup node take over with almost no downtime and may even approach zero downtime.
Using hot standby, two processors use hardware checkpoints to verify synchronization after each CPU instruction.
Warm standby—A slight delay occurs when a backup application takes over for another application.
Cold standby—The delay is a little longer than warm standby. In cold standby, the cluster software can't detect an outage and applications must be restarted manually.One or more spare processors are set aside to be used if an in-service processor fails.
When TIBCO applications are installed under a cluster, high-availability is best characterized as warm-standby.
