RAC one node connect string

 Hi ,

Am using RAC one node feature. I am able to connect to the database using the connect string:-

sqlplus sys/password@racone as sysdba

But am not able to connect to the database if i use the instance name as in:-

sqlplus sys/password@racone_1 as sysdba

I have tried the following changes in tnsnames.ora :-

1. RACONE =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = SCAN-host)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = racone) (SID = racone_1)
    )
  )
 

2.  RACONE =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = SCAN-host)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = racone) (INSTANCE_NAME= racone_1)
    )
  )

3.  RACONE =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = SCAN-host)(PORT = 1521))