Application developers can deal with this
sequence of failover events with generic or specific error handling in their applications,
or they can use the Transparent Application Failover functionality described
later in this chapter.
Failover and operating system platform
This type of failover capability has been available for many years. On Unix-based
platforms, vendors typically offer a simple failover solution that includes two
machines, a private network between them to monitor the heartbeat, shared disk,
and cluster software. No additional software is required from Oracle.
On Windows, Oracle includes Fail Safe, software that provides a GUI interface for
configuring the Oracle database for hardware failover that leverages Microsoft??™s
Cluster Server. The mechanics of the failover are the same??”a GUI is provided for
administrative convenience. (In recent releases, the Fail Safe Manager and Real
Applications Cluster Guard Manager have merged.)
Real Application Clusters
Oracle introduced Oracle Parallel Server (OPS), the predecessor to Real Application
Clusters, in 1989 on Digital Equipment Corporation??™s VAX clusters running the
Protecting Against System Failure | 269
VMS operating system, and on Unix in 1993.
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