Tried to create a standby controlfile from a RAC database, but it failed with ORA-00245 or ORA-245.
[oracle@primary01 ~]$ sqlplus / as sysdba
SQL> alter database create standby controlfile as '/tmp/standby.ctl';
alter database create standby controlfile as '/tmp/standby.ctl'
ERROR at line 1:
ORA-00245: control file backup failed; in Oracle RAC, target might not be on shared storage
ORA-00245 means that trying to backup controlfile to an unshared local storage is not allowable. You should seek for some shared storage among all nodes.
Solution to ORA-00245
We should backup the controlfile in a shared storage.
1. Shared File System
For example, NFS, GPFS or ACFS.
SQL> alter database create standby controlfile as '/shared_folder/standby.ctl';
If you don't have shared file system in this moment, you may consider to put it in ASM.
Create Standby ControlFile
SQL> alter database create standby controlfile as '+DATA/ORCLCDB/FLASHBACK/standby.ctl';
Copy Standby ControlFile out of ASM
This step is just like I said in How to Copy Files From One ASM Instance to Another.
[grid@primary01 ~]$ asmcmd cp +DATA/ORCLCDB/FLASHBACK/standby.ctl /tmp/
copying +DATA/ORCLCDB/FLASHBACK/standby.ctl -> /tmp//standby.ctl
[grid@primary01 ~]$ ll /tmp/standby.ctl
-rw-r----- 1 grid oinstall 23248896 Aug 26 12:36 /tmp/standby.ctl
However, I found that I can create a standby controfile file into a local folder in 19c RAC DB.