Introduction › CA ARCserve RHA Concepts › How High Availability Works

How High Availability Works

CA ARCserve High Availability (CA ARCserve HA) monitors all critical events, including global server failure and all database service failures, and either automatically or with a push of a button, initiates a switchover.

If the Master server becomes unavailable, its activities can be switched over automatically to a remote site (Replica). The switchover, which is transparent to the user, includes immediate startup of a synchronized standby database, and redirecting all users to it in minimum time. All this is done without any need to reconfigure either clients or the network.

Redirection can be based on the following methods:

• Move IP (if the standby site is implemented within the same network segment)
• Redirect DNS, can be used on a local network or when the remote standby site is located on a different IP network (cross-network switchover)
• Switch the server hostname/NetBIOS name

Note: You can also apply user-defined scripts that add or replace the built-in redirection methods. Identify Network Traffic Direction scripts are required to fully support custom, or customized, redirection methods. Custom scripts or batch files are used to identify the active server. This script determines if the forward or backward scenario will run when the scenario is started. The script runs on both the Master and Replica: the one that returns zero is active. If both return zero, a conflict is reported.

Redirection method selection is based on the requirements of the application being protected; certain methods may not apply to a particular scenario. For more information, see the application-specific Operation Guide.