一、日志文件损坏分类：
1、inactive 状态（不会造成数据丢失）
2、active、current状态（一般会造成数据丢失）
查看方法：
SQL> select group#,thread#,archived,status from v$log;
GROUP# THREAD# ARC STATUS
---------- ---------- --- ----------------
1 1 YES INACTIVE
2 1 NO CURRENT
3 1 YES INACTIVE
二、测试环境：
OS: Linux xxxxxxxx 2.6.18-238.el5 #1 SMP Thu Jan 13 15:51:15 EST 2011 x86_64 x86_64 x86_64 GNU/Linux
DB: oracle 11.2.0.1.6（非RAC)
三、inactive 状态日志文件损坏的恢复测试：
startup时错误日志：
SQL> startup
ORACLE instance started.
Total System Global Area 3156877312 bytes
Fixed Size 2217424 bytes
Variable Size 989858352 bytes
Database Buffers 2147483648 bytes
Redo Buffers 17317888 bytes
Database mounted.
ORA-03113: end-of-file on communication channel
Process ID: 29499
Session ID: 2273 Serial number: 5
alert错误日志：
Errors in file /u01/oracle/diag/rdbms/test/test/trace/test_lgwr_29457.trc:
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: '/u01/test/test/redo01.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_lgwr_29457.trc:
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: '/u01/test/test/redo01.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_29499.trc:
ORA-00313: open failed for members of log group 1 of thread
ORA-00312: online log 1 thread 1: '/u01/test/test/redo01.log'
USER (ospid: 29499): terminating the instance due to error 313
Instance terminated by USER, pid = 29499
这种情况下，只需将active的日志组删除，然后startup，如下：
SQL> startup mount;
ORACLE instance started.
Total System Global Area 3156877312 bytes
Fixed Size 2217424 bytes
Variable Size 989858352 bytes
Database Buffers 2147483648 bytes
Redo Buffers 17317888 bytes
Database mounted.
SQL> alter database drop logfile group 1;
Database altered.
SQL> alter database open;
Database altered.
四、active、current日志文件损坏：
startup时错误：
SQL> startup
ORACLE instance started.
Total System Global Area 3156877312 bytes
Fixed Size 2217424 bytes
Variable Size 989858352 bytes
Database Buffers 2147483648 bytes
Redo Buffers 17317888 bytes
Database mounted.
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
SQL> select group#,thread#,archived,status from v$log;
GROUP# THREAD# ARC STATUS
---------- ---------- --- ----------------
1 1 NO CURRENT
3 1 YES ACTIVE
2 1 YES INACTIVE
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 info