Performing a recovery without the current redo log
If a database is closed because of media failure, you should perform the following steps to recover it.
Try to open the database. You will get the information about the current damaged redo log group.
In a situation where a database is closed, the damaged online redo log file will not be archived. Thus, the command CLEAR LOGFILE will not clear the damaged file and a cancel-based recovery is required. You can only recover the database to the time before the current redo log is applied.
In order to perform the cancel-based recovery, you must find the sequence number for the current redo log via the SELECT * FROM V$LOG; statement.
Restore all datafiles from a previous backup.
Recover using the RECOVER UNTIL CANCEL command and stop before the current redo log is applied.
Open the database with the RESETLOGS option.
If the media failure is not corrected, you can recreate the log files onto another disk using the ALTER DATABASE DROP LOGFILE GROUP and ALATER DATABASE ADD LOG GROUP;
statements to drop and recreate the log files to a new location.