How to solve "RMAN-04014: startup failed: ORA-01261: Parameter db_recovery_file_dest destination string cannot be translated" during cloning

During an attempt to clone for active database I had created pfile with my desired value for the parameter db_recovery_file_dest, which was /fradata. Excerpt from init.ora used to start the instance (nomount):

cat initproddb01.ora |grep db_recovery_file_dest

*.db_recovery_file_dest='/fradata'

This directory exists on my auxilliary server and is indeed writable by the oracle software installation owner (for most installation, this user is called "oracle") After having started the instance, and executed the clone script:

DUPLICATE TARGET DATABASE
FOR STANDBY
FROM ACTIVE DATABASE
DORECOVER
SPFILE
SET DB_UNIQUE_NAME='STBY01' COMMENT 'Stanby db 1'
USING COMPRESSED BACKUPSET
NOFILENAMECHECK;

This message appears:

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of Duplicate Db command at 04/13/2021 08:07:31
RMAN-05501: aborting duplication of target database
RMAN-03015: error occurred in stored script Memory Script
RMAN-04014: startup failed: ORA-01261: Parameter db_recovery_file_dest destination string cannot be translated
ORA-01262: Stat failed on a file destination directory
Linux-x86_64 Error: 2: No such file or directory

Cause: The spfile that is created contains the target's db_recovery_file_dest setting, not the auxiliary's:

strings spfileproddb01.ora | grep db_recovery_file_dest
*.db_recovery_file_dest='/FRA' <--- this is inherited from the target database, and doesn't exist on the auxiliary server

Solution: Add a new spfile directive to your clone script:

SET DB_RECOVERY_FILE_DEST='/fradata'

and rerun.