启动数据库时报错：
SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-03113: end-of-file on communication channel
Process ID: 6685
Session ID: 1522 Serial number: 5

查看告警日志信息如下：
Mon Feb 06 10:54:30 2017
alter database open
Mon Feb 06 10:54:31 2017
Errors in file /u01/app/oracle/diag/rdbms/fpdb/fpdb/trace/fpdb_lgwr_6089.trc:
ORA-00313: open failed for members of log group 4 of thread 1
ORA-00312: online log 4 thread 1: '/u01/app/oracle/oradata/fpdb/redo04.log'
ORA-27037: unable to obtain file status
Linux-x86_64 Error: 2: No such file or directory

重启数据库到mount状态：
SQL> startup mount;
ORACLE instance started.

Total System Global Area 7699759104 bytes
Fixed Size            2243432 bytes
Variable Size         3539993752 bytes
Database Buffers     4143972352 bytes
Redo Buffers           13549568 bytes
Database mounted.

SQL> alter database clear logfile group 4;

Database altered.

SQL> set lines 200
SQL> select * from v$log;

    GROUP#    THREAD#  SEQUENCE#      BYTES  BLOCKSIZE      MEMBERS ARC STATUS           FIRST_CHANGE# FIRST_TIM NEXT_CHANGE# NEXT_TIME
---------- ---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- --------- ------------ ---------
     5        1        4784 1073741824       512        1 NO  CURRENT          4.8888E+11 06-FEB-17     2.8147E+14
     4        1           0 1073741824       512        1 NO  UNUSED          4.8888E+11 19-JAN-17     4.8888E+11 06-FEB-17

SQL> alter database open;

Database altered.