Oracle Error Message
RMAN-06522: KEEP FOREVER option is not supported without the recovery catalog
Reason for the Error
The KEEP FOREVER option was used, but it requires a connection to a recovery catalog database. The KEEP FOREVER option cannot be used when the backup repository is the target database control file. This is because information about this backup cannot be permanently stored. (If information is stored just in the control file it will be aged out depending on CONTROL_FILE_RECORD_KEEP_TIME initialization parameter.)
Solution
If a recovery catalog database is available, then connect to the recovery catalog and retry the command, otherwise use a different KEEP option. 6523, 1, “unused”