UniInt interface failover support

UniInt Phase 2 Failover provides support for cold, warm, or hot failover configurations. The PI to PI interface only supports the warm configuration. In the warm configuration, you can expect a small period of data loss during a single point of failure transition. This failover solution requires two copies of the interface to be installed on different interface nodes collecting data simultaneously from a single data source. Phase 2 Failover requires each interface to have access to a shared data file. Failover operation is automatic and operates with no user interaction. Each interface participating in failover has the ability to monitor and determine liveliness and failover status. To assist in administering system operations, the ability to manually trigger failover to a desired interface is also supported by Phase 2 Failover.