Client failover

The OPC UA adapter also supports client failover. Two adapters can be configured as part of a redundant group, so in the event of a connection loss to the failover endpoint or data source, the secondary adapter may take the place of the primary.

There are three client failover modes that the adapters can be configured to use: cold, warm and hot.

For more information about failover modes, failover scoring and configuring client-level failover, see Client failover.

Cold

If the adapters are operating in cold mode, the secondary adapter is configured but not started. After a failover event occurs, the secondary becomes primary and begins to collect and egress data.

Warm

When the adapters are configured in warm mode, the component is started and connected to the data source, but it is not collecting or egressing any data. Once a failover event occurs, the secondary will become primary and begin to collect and egress data.

Hot

In hot mode, both adapters are configured and started. They both collect and buffer data, but only the primary egresses data to the endpoint. When the secondary adapter becomes primary, it will send its buffered data to the endpoint.