If RACF® sysplex communication is wanted, the RACF database must be on a shared DASD. If sysplex communication is not wanted, you must turn off the data sharing bit in the data set name table (ICHRDSNT). See the MVS™ documentation on planning I/O configurations. This message might also be issued if RACF is installed for data sharing and an RVARY command was issued in an attempt to activate a data set that does not reside on a shared DASD. In this case, the data set is not activated. Message ICH501I follows this message.