System availability is crucial to the reliable operation of a power management system. In addition to hardware redundancy and failsafe software features, ETAP Real-Time offers redundant client-server setup. Two levels of system redundancy are offered:
Centralized redundant architecture employs an active server with multiple standby servers. Upon failure of the primary active server, a standby server is promoted to the active state allowing for a seamless fail-over scheme. Should the failed server recover, the newly promoted active server remains as the primary system server.
Distributed redundant architecture is similar to that of the centralized redundant scheme with the additional capability to independently manage multiple systems. This scheme supports communication loss as well as physical isolation of multiple sites resulting in islanded systems. In such cases, a standby server at each location will automatically be promoted to an active state and resume managing its local system independently. After reestablishing the connection between the multiple sites, the system is returned back to the normal state with one active server resuming the management of the multiple sites.