Some day, you may trap the following error message with your standby database alert log (seen on a 10.2.0.3):
RFS: No standby redo logfiles available
The reason for this message is most probably that you have cloned your standby database with
rman and configured your dataguard environment to directly write into redo log at standby (using
LGWR), instead of just transfering the archive log items from primary (using
ARCH), but have missed to provide the necessary standby redo log files.
RFS may also log
RFS: Unable to open standby log 9: 313 or something similar (the primary will also complain about connection problems to the standby destination target, which is the standby redo log, actually).
RFS: No standby redo logfiles available of size 104857600 bytes