Unable to perform an online backup.
An online backup has been performed in NO ARCHIVING mode.
An online backup can only be performed in ARCHIVING mode. Otherwise, an error occurs.
Check whether the database is running in ARCHIVING mode with the following command:
<How to change to ARCHIVING mode from NOARCHIVING mode>
1. Shut down the database.
2. Re-start the database.
3. Run the database in the CONTROL phase.
4. Change to ARCHIVING mode using the ALTER DATABASE ARCHIVELOG statement.
<Execute an online backup in ARCHIVING MODE>
1. Run the database in the SERVICE phase.
2. Re-start backup.