Oracle Real Application Clusters (Oracle RAC) allows for better performance, high availability and failover in your Oracle DB environment. Connecting to such an environment via the full Oracle Client generally requires multiple addressed to be listed (at least one for each node in the RAC) within the Local Naming Parameters file (tnsnames.ora). However, TDM requires a single hostname/address to connect to. This could cause problems connecting to Oracle from TDM and/or negate some of the load balancing features of Oracle RAC when connecting from TDM.
Supported TDM versions connecting to Supported Oracle data sources/targets in an Oracle RAC configuration.
Connecting to Oracle RAC via TDM requires a Single Client Access Name (SCAN). Per the Oracle documentation:
Refer to the TDM Documentation for details on how to create connections for TDM components as needed.