ORA-01232: cannot start online backup - file [string] is being made read-only
Cause: An attempt to start an online backup found that one of the files is in transition to read-only mode.
Action: Wait for the transition to complete and then retry the command, if this is an ALTER DATABASE BEGIN BACKUP command, or take the backup without any begin or end commands, if this is an ALTER TABLESPACE BEGIN BACKUP command.
Error Type: ORA