Corrupted Redolog file and no backup

[nabeel]

Additional information:
Because log group 2 is the current log group, it will not have been archived. Using the CLEAR LOGFILE command is of no use because:

SQL> alter database clear unarchived logfile group 2;
ORA-01624: log 2 needed for crash recovery of thread 1
ORA-00312: online log 2 thread 1: 'disk1/archive/log2a.rdo'

Try Performing Incomplete recovery therefore, First you must note the current log sequence number by issuing this statement

SQL> select * from v$log;

Use the ALTER DATABASE DROP LOG GROUP and ALTER DATABASE ADD LOG GROUP commands to create the log files manually. Because you performed incomplete recovery, the database should now be backed up.