经验总结：
联机日志分为当前联机日志和非当前联机日志，非当前联机日志的损坏是比较简单的，一般通过clear命令就可以解决问题。
损坏非当前联机日志：
1、启动数据库，遇到ORA-00312 or ORA-00313错误，如:
ORA-00313: open failed for members of log group 4 of thread 1
ORA-00312: online log 3 thread 1: '/opt/oracle/db04/oradata/ORCL/redo03.log'
从这里我们知道日志组1的数据文件损坏或丢失了
从报警文件可以看到更详细的信息
2、查看V$log视图:
SQL>; select group#,sequence#,archived,status from v$log;
GROUP# SEQUENCE# ARC STATUS
---------- ---------- --- ----------------
1 54 YES INACTIVE
2 55 NO CURRENT
3 53 YES INACTIVE
可以知道，该组是非当前状态，而且已经归档。
3、用CLEAR命令重建该日志文件
SQL>;alter database clear logfile group 3;
如果是该日志组还没有归档，则需要用
SQL>;alter database clear unarchived logfile group 3;
4、打开数据库，重新备份数据库
SQL>;alter database open;
说明：
1)、如果损坏的是非当前的联机日志文件，一般只需要clear就可以重建该日志文件，但是如果该数据库处于归档状态但该日志还没有归档，就
需要强行clear。
2)、建议clear，特别是强行clear后作一次数据库的全备份。
3)、此方法适用于归档与非归档数据库。
损坏当前联机日志：
归档模式下当前日志的损坏有两种情况，
一、是数据库是正常关闭，日志文件中没有未决的事务需要实例恢复，当前日志组的损坏就可以直接用alter database clear unarchived
logfile group n来重建。
二、是日志组中有活动的事务，数据库需要媒体恢复，日志组需要用来同步，有两种补救办法
A. 最好的办法就是通过不完全恢复，可以保证数据库的一致性，但是这种办法要求在归档方式下，并且有可用的备份
B. 通过强制性恢复，但是可能导致数据库不一致。
下面分别用来说明这两种恢复方法
5.1.2.1 通过备份来恢复
1、打开数据库，会遇到一个类似的错误
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: 'D:\ORACLE\ORADATA\TEST\REDO01.LOG'
ORA-27041: unable to open file
OSD-04002: unable to open file
O/S-Error: (OS 2) 系统找不到指定的文件
2、查看V$log，发现是当前日志
SQL>; select group#,sequence#,archived,status from v$log;
GROUP# SEQUENCE# ARCHIVED STATUS
---------- ---------- -------- ----------------
1 1 NO CURRENT
2 2
YES INACTIVE
3 3 YES INACTIVE
3、发现clear不成功
SQL>; alter database clear unarchived logfile group 1;
alter database clear unarchived logfile group 1
*
ERROR at line 1:
ORA-01624: log 1 needed for crash recovery of thread 1
ORA-00312: online log 1 thread 1: 'D:\ORACLE\ORADATA\TEST\REDO01.LOG'
4、拷贝有效的数据库的全备份，并不完全恢复数据库
可以采用获取最近的SCN的办法用until scn恢复或用until cnacel恢复
recover database until cancel
先选择auto，尽量恢复可以利用的归档日志，然后重新
recover database until cancel
这次输入cancel，完成不完全恢复，也就是说恢复两次。
如：
SQL>; recover database until cancel;
Auto
……
SQL>; recover database until cancel;
Cancel;
5、利用alter database open resetlogs打开数据库
说明：
1、这种办法恢复的数据库是一致的不完全恢复，会丢失当前联机日志中的事务数据
2、这种方法适合于归档数据库并且有可用的数据库全备份。
3、恢复成功之后，记得再做一次数据库的全备份。
4、建议联机日志文件一定要实现镜相在不同的磁盘上，避免这种情况的发生，因为任何数据的丢失对于生产来说都是不容许的。
如果没有备份，进行强制性恢复
1、打开数据库，会遇到一个类似的错误
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: 'D:\ORACLE\ORADATA\TEST\REDO01.LOG'
ORA-27041: unable to open file
OSD-04002: unable to open file
O/S-Error: (OS 2) 系统找不到指定的文件
2、查看V$log，发现是当前日志
SQL>; select group#,sequence#,archived,status from v$log;
GROUP# SEQUENCE# ARCHIVED STATUS
---------- ---------- -------- ----------------
1 1 NO CURRENT
2 2 YES INACTIVE
3 3 YES INACTIVE
3、发现clear不成功
SQL>; alter database clear unarchived logfile group 1;
alter database clear unarchived logfile group 1
*
ERROR at line 1:
ORA-01624: log 1 needed for crash recovery of thread 1
ORA-00312: online log 1 thread 1: 'D:\ORACLE\ORADATA\TEST\REDO01.LOG'
4、把数据库down掉
SQL>;shutdown immediate
5、在init<sid>;.ora中加入如下参数
_allow_resetlogs_corruption=TRUE
6、重新启动数据库,利用until cancel恢复
SQL>;recover database until cancel;
Cancel
如果出错，不再理会，发出
SQL>;alter database open resetlogs;
7、数据库被打开后，马上执行一个full export
8、shutdown数据库,去掉_all_resetlogs_corrupt参数
9、重建库
10、import并完成恢复
11、建议执行一下ANALYZE TABLE ...VALIDATE STRUCTURE CASCADE;
说明：
1、该恢复方法是没有办法之后的恢复方法，一般情况下建议不要采用，因为该方法可能导致数据库的不一致
2、该方法也丢失数据，但是丢失的数据没有上一种方法的数据多，主要是未写入数据文件的已提交或未提交数据。
3、建议成功后严格执行以上的7到11步，完成数据库的检查与分析
4、全部完成后做一次数据库的全备份
5、建议联机日志文件一定要实现镜相在不同的磁盘上，避免这种情况的发生，因为任何数据的丢失对于生产来说都是不容许的。
用startup force试试！
allow_resetlogs_corruption=TRUE
这个我用过,数据库可以起来,但是数据是不是完整,还不一定,但数据库可以起来
需要重新启动一个log
SQL>;RECOVER DATABASE UNTILE CANCEL;
数据库会自己找一些它所需要的文件来进行数据库恢复；
SQL>;ALTER DATABASE OPEN RESETLOGS;
不知道你做没有做归档，如果做了，那么这个RECOVER还是比较有效的
没做的话估计不行
参考2：
SQL>host oerr ora 314
00314, 00000, "log %s of thread %s, expected sequence# %s doesn't match %s"
// *Cause: The online log is corrupted or is an old version.
// *Action: Find and install correct version of log or reset logs.
SQL> startup
ORACLE instance started.
Total System Global Area 167772160 bytes
Fixed Size 1266392 bytes
Variable Size 138415400 bytes
Database Buffers 25165824 bytes
Redo Buffers 2924544 bytes
Database mounted.
ORA-00314: log 2 of thread 1, expected sequence# 53 doesn't match 2
ORA-00312: online log 2 thread 1: '/opt/oracle/oradata/xxxdb/redo02.log'
select open_mode from v$database;
SQL> select open_mode from v$database;
OPEN_MODE
----------
MOUNTED
select group#,sequence#,archived,status from v$log;
SQL> host oerr ora 314
00314, 00000, "log %s of thread %s, expected sequence# %s doesn't match %s"
// *Cause: The online log is corrupted or is an old version.
// *Action: Find and install correct version of log or reset logs.
>alter database clear unarchived logfile group 1
ORA-01624: log 1 needed for crash recovery of thread 1
ORA-00312: online log 1 thread 1: '/dbase/oracle7/dbs/log1orac.dbf'
alter database clear unarchived logfile group 1
SQL> select group#,sequence#,archived,status from v$log;
GROUP# SEQUENCE# ARC STATUS
---------- ---------- --- ----------------
1 52 YES INACTIVE
3 51 YES INACTIVE
2 53 NO CURRENT
alter database clear unarchived logfile group 2
SQL> alter database clear unarchived logfile group 2
2 ;
alter database clear unarchived logfile group 2
*
ERROR at line 1:
ORA-01624: log 2 needed for crash recovery of instance xxxdb (thread 1)
ORA-00312: online log 2 thread 1: '/opt/oracle/oradata/xxxdb/redo02.log'
ORA-00314:
log string of thread string, expected sequence# string doesn't match string
Cause: The online log is corrupted or is an old version.
Action: Find and install correct version of log or reset logs.
SQL> alter system switch logfile;
alter system switch logfile
*
ERROR at line 1:
ORA-01109: database not open
SQL> select group#,sequence#,archived,status from v$log;
GROUP# SEQUENCE# ARC STATUS
---------- ---------- --- ----------------
1 52 YES INACTIVE
3 51 YES INACTIVE
2 53 NO CURRENT
SQL>recover database until cancel
ORA-00279: change 1692814 generated at 07/18/2010 21:10:36 needed for thread 1
ORA-00289: suggestion : /opt/oracle/oradata/archive/1_53_724438720.dbf
ORA-00280: change 1692814 for thread 1 is in sequence #53
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
auto
ORA-00308: cannot open archived log
'/opt/oracle/oradata/archive/1_53_724438720.dbf'
ORA-27037: unable to obtain file status
Linux Error: 2: No such file or directory
Additional information: 3
ORA-00308: cannot open archived log
'/opt/oracle/oradata/archive/1_53_724438720.dbf'
ORA-27037: unable to obtain file status
Linux Error: 2: No such file or directory
Additional information: 3
ORA-01547: warning: RECOVER succeeded but OPEN RESETLOGS would get error below
ORA-01194: file 1 needs more recovery to be consistent
ORA-01110: data file 1: '/opt/oracle/oradata/xxxdb/system01.dbf'
SQL>alter database open resetlogs
2 ;
Sun Jul 18 23:55:36 2010
SMON: enabling cache recovery
Sun Jul 18 23:55:37 2010
Errors in file /opt/oracle/admin/xxxdb/udump/xxxdb_ora_4682.trc:
ORA-00600: internal error code, arguments: [2662], [0], [1692821], [0], [1693668], [8388617], [], []
Sun Jul 18 23:55:41 2010
Errors in file /opt/oracle/admin/xxxdb/udump/xxxdb_ora_4682.trc:
ORA-00600: internal error code, arguments: [2662], [0], [1692821], [0], [1693668], [8388617], [], []
Sun Jul 18 23:55:41 2010
Error 600 happened during db open, shutting down database
USER: terminating instance due to error 600
Instance terminated by USER, pid = 4682
ORA-1092 signalled during: alter database open resetlogs
SQL> conn / as sysdba
Connected to an idle instance.
SQL> startup mount
ORACLE instance started.
Total System Global Area 167772160 bytes
Fixed Size 1266392 bytes
Variable Size 138415400 bytes
Database Buffers 25165824 bytes
Redo Buffers 2924544 bytes
Database mounted.
SQL> show parameter undo
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
undo_management string AUTO
undo_retention integer 900
undo_tablespace string UNDOTBS2
alter system set undo_tablespace='UNDOTBS1' scope=spfile;
show parameter undo
shutdown immediate
startup mount
show parameter undo
alter database open;
SQL> alter system set undo_tablespace='UNDOTBS1' scope=spfile;
show parameter undo
System altered.
SQL> shutdown immediate
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
undo_management string AUTO
undo_retention integer 900
undo_tablespace string UNDOTBS2
SQL> startup mount
show parameter undo
ORA-01109: database not open
Database dismounted.
ORACLE instance shut down.
SQL> ORACLE instance started.
Total System Global Area 167772160 bytes
Fixed Size 1266392 bytes
Variable Size 138415400 bytes
Database Buffers 25165824 bytes
Redo Buffers 2924544 bytes
Database mounted.
SQL>
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
undo_management string AUTO
undo_retention integer 900
undo_tablespace string UNDOTBS1
SQL> alter database open;
Database altered.
参看：
http://www.chinaunix.net/jh/19/605827.html
4、拷贝有效的数据库的全备份，并不完全恢复数据库
可以采用获取最近的SCN的办法用until scn恢复或用until cnacel恢复
recover database until cancel
先选择auto，尽量恢复可以利用的归档日志，然后重新
recover database until cancel
这次输入cancel，完成不完全恢复，也就是说恢复两次。