RMAN-06479: control file copy 'string' cannot be found on disk
Cause: The CHANGE CONTROLFILECOPY AVAILABLE command was used, but the control file copy cannot be found on disk.
Action: If the storage containing the control file copy has been removed from the host, then restore it and retry the command. If the control file copy is permanently gone, then issue the CHANGE CONTROLFILECOPY DELETE command for this control file.