alert日志错误：
Completed: ALTER DATABASE MOUNT
Fri Apr 25 16:49:21 2014
ALTER DATABASE OPEN
Beginning crash recovery of 1 threads
parallel recovery started with 2 processes
Started redo scan
Errors in file /u01/oracle/diag/rdbms/test/test/trace/test_ora_29862.trc:
ORA-00313: open failed for members of log group 3 of thread 1
ORA-00312: online log 3 thread 1: '/u01/test/test/redo03.log'
ORA-27037: unable to obtain file status
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
Aborting crash recovery due to error 313
Errors in file /u01/oracle/diag/rdbms/test/test/trace/test_ora_29862.trc:
ORA-00313: open failed for members of log group 3 of thread 1
ORA-00312: online log 3 thread 1: '/u01/test/test/redo03.log'
ORA-27037: unable to obtain file status
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
Errors in file /u01/oracle/diag/rdbms/test/test/trace/test_ora_29862.trc:
ORA-00313: open failed for members of log group 3 of thread 1
ORA-00312: online log 3 thread 1: '/u01/test/test/redo03.log'
ORA-27037: unable to obtain file status
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
ORA-313 signalled during: ALTER DATABASE OPEN...
Fri Apr 25 16:49:21 2014
Errors in file /u01/oracle/diag/rdbms/test/test/trace/test_m000_29874.trc:
ORA-00313: open failed for members of log group 3 of thread 1
ORA-00312: online log 3 thread 1: '/u01/test/test/redo03.log'
ORA-27037: unable to obtain file status
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
Checker run found 2 new persistent data failures
这种情况下无法删除active联机日志，尝试各种删除方式都会报错，如下：
SQL> alter database drop logfile group 3;
alter database drop logfile group 3
*
ERROR at line 1:
ORA-01624: log 3 needed for crash recovery of instance test (thread 1)
ORA-00312: online log 3 thread 1: '/u01/test/test/redo03.log'
SQL> alter database clear logfile group 3;
alter database clear logfile group 3
*
ERROR at line 1:
ORA-01624: log 3 needed for crash recovery of instance test (thread 1)
ORA-00312: online log 3 thread 1: '/u01/test/test/redo03.log'
SQL> alter database clear unarchived logfile group 3;
alter database clear unarchived logfile group 3
*
ERROR at line 1:
ORA-01624: log 3 needed for crash recovery of instance test (thread 1)
ORA-00312: online log 3 thread 1: '/u01/test/test/redo03.log'