Oracle 日志文件修复技巧（二）

状态为active日志组损坏

先查看日志组的状态

SQL> select  GROUP# ,SEQUENCE#  ,MEMBERS, ARCHIVED , STATUS from v$log;

    GROUP#  SEQUENCE#    MEMBERS ARC STATUS

---------- ---------- ---------- --- ----------------

         1          9          2 NO  CURRENT

         2          8          2 YES ACTIVE  是active 表示该组的日志信息要用户实例恢复

         3          6          2 YES INACTIVE

如果损坏的是active日志组

修复思路：

立即执行一次：alter system checkpoint ;    #该命令只能在open状态下执行

将active状态转换为inactive

i. 转换成功：变为inactive 就去按照inactive的方法去修复

ii. 转换失败：只能做不完全恢复（日志记录数据丢失) 恢复到有日志的那一个时刻

 修复案例

把第四组设置为活动组 

SQL> select  GROUP# ,SEQUENCE#  ,MEMBERS, ARCHIVED , STATUS

   from v$log; 

    GROUP#  SEQUENCE#    MEMBERS ARC STATUS

---------- ---------- ---------- --- ----------------

         1         19          2 NO  CURRENT

         2         16          2 YES INACTIVE

         3         17          3 YES ACTIVE

         4         18          2 YES ACTIVE  

模拟故障 删除active日志组的所有成会员 

SQL> select member from v$logfile where group#=4;

MEMBER

---------------------------------------------

/u01/app/oracle/redo401.log

/u01/app/oracle/redo402.log

删除日志文件

rm -rf u01/app/oracle/redo401.log

rm -rf u01/app/oracle/redo402.log

假设知道日志组4故障

SQL> select  GROUP# ,SEQUENCE#  ,MEMBERS, ARCHIVED , STATUS

   from v$log; 

    GROUP#  SEQUENCE#    MEMBERS ARC STATUS

---------- ---------- ---------- --- ----------------

         1          9          2 YES ACTIVE

         2          8          2 YES INACTIVE

         3         11          2 NO  CURRENT

         4         10          2 YES ACTIVE   活动组

走active修复流程

alter system checkpoint;

SQL>  select  GROUP# ,SEQUENCE#  ,MEMBERS, ARCHIVED , STATUS

   from v$log; 

    GROUP#  SEQUENCE#    MEMBERS ARC STATUS

---------- ---------- ---------- --- ----------------

         1          9          2 YES INACTIVE

         2          8          2 YES INACTIVE

         3         11          2 NO  CURRENT

         4         10          2 YES INACTIVE 变为inactive 

SQL>  alter database clear logfile group 4;

SQL>  select  GROUP# ,SEQUENCE#  ,MEMBERS, ARCHIVED , STATUS

   from v$log; 

    GROUP#  SEQUENCE#    MEMBERS ARC STATUS

---------- ---------- ---------- --- ----------------

         1          9          2 YES INACTIVE

         2          8          2 YES INACTIVE

         3         11          2 NO  CURRENT

         4          0          2 YES UNUSED

SQL>  alter system switch logfile ;

SQL>  select  GROUP# ,SEQUENCE#  ,MEMBERS, ARCHIVED , STATUS

   from v$log; 

    GROUP#  SEQUENCE#    MEMBERS ARC STATUS

---------- ---------- ---------- --- ----------------

         1          9          2 YES INACTIVE

         2          8          2 YES INACTIVE

         3         11          2 YES ACTIVE

         4         12          2 NO  CURRENT

虚

状态current日志组损坏

当前日志组损坏，而且数据库实例宕掉

前提：归档模式，有备份

SQL>  select  GROUP# ,SEQUENCE#  ,MEMBERS, ARCHIVED , STATUS

  from v$log;

    GROUP#  SEQUENCE#    MEMBERS ARC STATUS

---------- ---------- ---------- --- ----------------

         1         19          2 YES ACTIVE

         2         17          2 YES ACTIVE

         3         18          2 YES ACTIVE

         4         20          2 NO  CURRENT

SQL>  insert into scott.emp (empno,ename ,sal) values(3,'bob',1000);

SQL>  insert into scott.emp (empno,ename ,sal) values(4,'jim',1000);

SQL>  commit;

SQL>  select empno ,ename ,sal from scott.emp ;

     EMPNO ENAME             SAL

---------- ---------- ----------

         1 tom              1000

         2 mary             1000

         3 bob              1000   ----日志在日志组4 

         4 jim               1000

 select  GROUP# ,SEQUENCE#  ,MEMBERS, ARCHIVED , STATUS

  from v$log;

  GROUP#  SEQUENCE#    MEMBERS ARC STATUS

---------- ---------- ---------- --- ----------------

         1         19          2 YES ACTIVE

         2         17          2 YES ACTIVE

         3         18          2 YES ACTIVE

         4         20          2 NO  CURRENT 当前日志组还是4

删除当前日志组4的所有日志文件

SQL> select member from v$logfile where group#=4;

MEMBER

--------------------------------------------------------------------------------

/u01/app/oracle/redo401.log

/u01/app/oracle/redo402.log

SQL> shutdown immediate

rm -rf u01/app/oracle/redo401.log

rm -rf u01/app/oracle/redo402.log

启动数据库报错：

SQL> startup

ORA-00313: open failed for members of log group 4 of thread 1

ORA-00312: online log 4 thread 1: '/u01/app/oracle/redo402.log'

ORA-27037: unable to obtain file status

Linux-x86_64 Error: 2: No such file or directory

Additional information: 3

ORA-00312: online log 4 thread 1: '/u01/app/oracle/redo401.log'

ORA-27037: unable to obtain file status

Linux-x86_64 Error: 2: No such file or directory

Additional information: 3

启动数据库到mount

SQL> startup mount;

SQL> select status from v$instance;

STATUS

------------

MOUNTED

通过提示确定日志文件的问题：

cd u01/app/oracle/diag/rdbms/orcl/orcl/trace

vi alert_orcl.log

ORA-00313: open failed for members of log group 4 of thread

online log 4 thread 1: '/u01/app/oracle/redo402.log'

online log 4 thread 1: '/u01/app/oracle/redo401.log'

去看日志组的状态

SQL>  select  GROUP# ,SEQUENCE#  ,MEMBERS, ARCHIVED , STATUS

  from v$log;

    GROUP#  SEQUENCE#    MEMBERS ARC STATUS

---------- ---------- ---------- --- ----------------

         1         19          2 YES INACTIVE

         4         22          2 NO  CURRENT  2个成员，第四组当前组全挂 实例倒掉

         3         17          3 YES INACTIVE

         2         21          2 YES INACTIVE

alter system switch logfile   #该命令只能在open下输入，切换日志失败 

*

ERROR at line 1:

ORA-01109: database not open

SQL> alter database clear logfile group 4 ;     #失败

alter database clear logfile group 4

*

ERROR at line 1:

ORA-01624: log 4 needed for crash recovery of instance orcl (thread 1)

ORA-00312: online log 4 thread 1: '/u01/app/oracle/red401.log'

ORA-00312: online log 4 thread 1: '/u01/app/oracle/red402.log'

#该日志的信息要用于实例恢复，必须在

SQL> alter database drop logfile group 4 ;

alter database drop logfile group 4

*

ERROR at line 1:

ORA-01623: log 4 is current log for instance orcl (thread 1) - cannot drop

ORA-00312: online log 4 thread 1: '/u01/app/oracle/redo401.log'

ORA-00312: online log 4 thread 1: '/u01/app/oracle/redo402.log'

结论：只能做不完全恢复

就是恢复数据库到有日志的地方

查看数据库现在还有日志结束点在哪里？

SQL> select GROUP#,SEQUENCE# , STATUS , ARCHIVED, FIRST_CHANGE#,NEXT_CHANGE# from v$log; 

  GROUP#  SEQUENCE# STATUS           ARC FIRST_CHANGE# NEXT_CHANGE#

---------- ---------- ---------------- --- ------------- ------------

         1         19 INACTIVE         YES       3848618      3848814

         4         22 CURRENT          NO        3850056   2.8147E+14

         3         17 INACTIVE         YES       3848597      3848600

         2         21 INACTIVE         YES       3849537      3850056

日志组4没有了 ，找日志组4之前 日志组是的序列是22 找序列21 

可以恢复到序列21

可以恢复到scn  3850056

或者 recover database until cancel ;  （自动搜寻可以用于恢复的日志，没有了结束）

$ rman target         # 必须有备份

RMAN> restore database ;

操作：

$ sqlplus as sysdba

SQL> recover database until cancel ;

Media recovery complete.

SQL> alter database open resetlogs; 

Database altered.

检查一下

SQL> select GROUP#,SEQUENCE# , STATUS , ARCHIVED, FIRST_CHANGE#,NEXT_CHANGE#

    from v$log;

  2

    GROUP#  SEQUENCE# STATUS           ARC FIRST_CHANGE# NEXT_CHANGE#

---------- ---------- ---------------- --- ------------- ------------

         1          1 CURRENT          NO        1027005   2.8147E+14

         2          0 UNUSED           YES             0            0

         3          0 UNUSED           YES             0            0

         4          0 UNUSED           YES             0            0

检查备份后做的操作，也就是日志组4中记录的事务的操作，全部丢失

SQL> select empno ,ename ,sal from scott.emp ;

     EMPNO ENAME             SAL

---------- ---------- ----------

         1 tom              1000

         2 mary             1000

3 4都丢失了  

证明：当前日志组丢失，则100%丢失数据！

建议做一次全备

delete  backup ;

backup database ;

状态current日志组损坏

当前日志组损坏，而且数据库实例宕掉

非归档模式，没有备份

SQL> archive log list ;

Database log mode              No Archive Mode

Automatic archival             Disabled

Archive destination            USE_DB_RECOVERY_FILE_DEST

Oldest online log sequence     4

Current log sequence           6

 

没有备份，没有归档.

1. 添加一个日志组

SQL> alter database add logfile group 4 ('/u01/app/oracle/redo401.log','/u01/app/oracle/redo402.log') size 50M;

SQL> select GROUP#, SEQUENCE# ,STATUS ,ARCHIVED  from v$log;

    GROUP#  SEQUENCE# STATUS           ARC

---------- ---------- ---------------- ---

         1          4 INACTIVE         NO

         2          5 INACTIVE         NO

         3          6 CURRENT          NO

         4          0 UNUSED           YES

2. 切换一次，为当前日志组

SQL> alter system switch logfile ;

SQL> select GROUP#, SEQUENCE# ,STATUS ,ARCHIVED  from v$log;

    GROUP#  SEQUENCE# STATUS           ARC

---------- ---------- ---------------- ---

         1          4 INACTIVE         NO

         2          5 INACTIVE         NO

         3          6 ACTIVE           NO

         4          7 CURRENT          NO

3. 执行DML 生成日志 写入日志组4 

SQL> select count(*) from scott.emp ;

  COUNT(*)

----------

        14

SQL> delete from scott.emp ;

14 rows deleted.

SQL> commit;

SQL> select count(*) from scott.emp ;

  COUNT(*)

----------

         0

再次查看日志组

SQL> select GROUP#, SEQUENCE# ,STATUS ,ARCHIVED  from v$log;

    GROUP#  SEQUENCE# STATUS           ARC

---------- ---------- ---------------- ---

         1          4 INACTIVE         NO

         2          5 INACTIVE         NO

         3          6 ACTIVE           NO

         4          7 CURRENT          NO

4. 删除所有当期日志组成员

SQL> select member from v$logfile where group#=4;

MEMBER

--------------------------------------------------------------------------------

/u01/app/oracle/redo401.log

/u01/app/oracle/redo402.log

rm -rf u01/app/oracle/redo401.log

rm -rf u01/app/oracle/redo402.log

5. 强制关闭数据库

shutdown abort; 

6. 启动数据库

SQL> startup

ORACLE instance started.

Total System Global Area  534462464 bytes

Fixed Size                  2215064 bytes

Variable Size             369099624 bytes

Database Buffers          159383552 bytes

Redo Buffers                3764224 bytes

Database mounted.

ORA-00313: open failed for members of log group 4 of thread 1

ORA-00312: online log 4 thread 1: '/u01/app/oracle/redo402.log'

ORA-27037: unable to obtain file status

Linux-x86_64 Error: 2: No such file or directory

Additional information: 3

ORA-00312: online log 4 thread 1: '/u01/app/oracle/redo401.log'

ORA-27037: unable to obtain file status

Linux-x86_64 Error: 2: No such file or directory

Additional information: 3

log 4 thread 1: '/u01/app/oracle/redo401.log'

 log 4 thread 1: '/u01/app/oracle/redo402.log'

两个日志文件 也就是第4组全部损坏

 select GROUP#, SEQUENCE# ,STATUS ,ARCHIVED  from v$log;

    GROUP#  SEQUENCE# STATUS           ARC

---------- ---------- ---------------- ---

         1          4 INACTIVE         NO

         4          7 CURRENT          NO     # 第4组是current状态

         3          6 ACTIVE           NO

         2          5 INACTIVE         NO

第4组是current状态，所以按照恢复流程要做不完恢复

该数据库是测试库，没有任何备份，不处于归档模式 ，不能做不完全恢复

7. 恢复

只有设置隐含参数强制启动数据库,启动后要用exp/imp把数据库全库导出，删除数据库，重建库，再导入。

强制恢复， 这种方法可能会导致数据不一致

SQL> alter system set "_allow_resetlogs_corruption" =true scope=spfile;

SQL> shutdown immediate;

ORACLE instance shut down.

SQL> startup mount;

ORACLE instance started.

Total System Global Area  534462464 bytes

Fixed Size                  2215064 bytes

Variable Size             369099624 bytes

Database Buffers          159383552 bytes

Redo Buffers                3764224 bytes

Database mounted.

SQL> show parameter _allow

NAME                                 TYPE        VALUE

------------------------------------ ----------- ------------------------------

_allow_resetlogs_corruption          boolean     TRUE

 

用open resetlogs打开数据库 

 alter database open resetlogs

*

ERROR at line 1:

ORA-01139: RESETLOGS option only valid after an incomplete database recovery

recover database until cancel;

输入cancel 

SQL> alter database open resetlogs;      #执行该命令把数据库打开

select count(*) from scott.emp ; 

  COUNT(*)

----------

        14   #刚才删除的事务的操作丢失了

只要current日志丢失，保存在current日志操作的数据库全部丢失  100%

总结：生产库，测试库都应该有备份策略。

可能遇到的故障：

 alter database open resetlogs

*

ERROR at line 1:

ORA-00603: ORACLE server session terminated by fatal error

ORA-00604: error occurred at recursive SQL level 1

ORA-01115: IO error reading block from file  (block # )

ORA-01110: data file 1: '+DATA/orcl/datafile/system.256.822001323'

ORA-15081: failed to submit an I/O operation to a disk

ORA-00604: error occurred at recursive SQL level 1

ORA-01115: IO error reading block from file  (block # )

ORA-01110: data file 1: '+DATA/orcl/datafile/system.256.822001323'

ORA-15081: failed to submit an I/O operation to a disk

ORA-01092: ORACLE instance terminated. Disconnection forced

ORA-00600: internal error code, arguments: [2662], [0], [1020720], [0],

[1028485], [12583040], [], [], [], [], [], []

Process ID: 32494

Session ID: 1 Serial number: 5

这里主要看2点：

（1）使用了_allow_resetlogs_corruption 参数

（2）这种情况下，可能会报ORA-600[2662]（SCN有关）和 ORA-600[4000]（回滚段有关）的错误。

 错误1：ORA-600[2662]（SCN有关） 解决方案

 

这次一开始这个库报ORA-600[2662]错误:

Mon Aug 23 09:37:00 2010

Errors in file oracle/QAS/saptrace/usertrace/qas_ora_852096.trc:

ORA-00600: internal error code, arguments: [2662], [0], [130131504], [0], [130254136], [4264285], [], []

Mon Aug 23 09:37:02 2010

Errors in file oracle/QAS/saptrace/usertrace/qas_ora_852096.trc:

ORA-00600: internal error code, arguments: [2662], [0], [130131506], [0], [130254136], [4264285], [], []

 ORA-600 [2662] “Block SCN is ahead of Current SCN”错误是当数据块中的SCN领先于current SCN，由于后台进程或服务进程都会比对UGA中的dependent SCN和数据库当前的SCN，如果数据库当前SCN小于dependent SCN，那么该进程就会报ORA-600 [2662]错误，如果遭遇该错误的是服务进程，那么服务进程一般会异常终止；如果遭遇该错误的是后台进程譬如SMON,则会导致实例CRASH。

ORA-600 [2662]错误可以能由以下几种情况引起:

1.启用隐含参数_ALLOW_RESETLOGS_CORRUPTION后，以resetlogs形式打开数据库；这种情况下发生2662错误，根本原因是没有完全前滚导致控制文件中的SCN滞后于数据块中的SCN。

2.硬件故障导致数据库没法写控制文件和联机日志文件

3.错误的部分恢复数据库

4.恢复了控制文件，但是没有使用recover database using backup controlfile进行恢复

5.数据库crash后设置了_DISABLE_LOGGING隐含参数

6.在并行服务器环境中DLM存在问题

该错误的5个参数的具体含义如下:

ARGUMENTS:

Arg [a] Current SCN WRAP

Arg [b] Current SCN BASE

Arg [c] dependent SCN WRAP

Arg [d] dependent SCN BASE

Arg [e] Where present this is the DBA where the dependent SCN came from.

我们的case当中dependent SCN为130254136，而当前SCN为130131506，其差值为122630；从以上告警日志中可以看到数据库的当前SCN是在不断缓慢增长的，当我们遭遇到2662错误时，很滑稽的一点是只要不断重启数据库保持current SCN的增长，一段时间后2662错误会不药而愈。当然我们也可以不用这种笨办法，10015事件可以帮助我们调整数据库当前SCN:

/* 当数据库处于mount状态，可以使用10015事件来调整scn */

alter session  set events '10015 trace name adjust_scn level 1';

* 这里可以设置level 2..10等 (level 1是在每次打开数据库时scn增加1000k)*/

 

总结：

ORA-00600: internal error code, arguments: [2662], [0], [130131506], [0], [130254136], [4264285], [], []

解决方法：不停的重启或者执行：alter session  set events '10015 trace name adjust_scn level 1';

错误2：

ORA-600[4000]（回滚段有关）的错误

ORA-00600: internal error code, arguments: [4000], [8], [], [], [], [], [], []

Wed Aug 25 07:43:53 2010

ORA-00704: bootstrap process failure

ORA-00704: bootstrap process failure

ORA-00600: internal error code, arguments: [4000], [8], [], [], [], [], [], []

Wed Aug 25 07:43:53 2010

Error 704 happened during db open, shutting down database

解决方法：

重启数据库过程中遭遇了ORA-600 [4000]错误，该错误一般当Oracle尝试读取数据字典(主要是undo$基表)中记录的USN对应的回滚段失败引起.，通过设置隐式参数_corrupted_rollback_segments可以一定程度上规避该错误，强制打开数据库,其Argument[a]代表造成读取失败的USN(undo segment number)，但实际上有问题的回滚段可能不止这一个:

/* 通过strings工具从system表空间上找回各回滚段的名字  */

$strings system.dbf |grep _SYSSMU|less

_SYSSMU1$

_SYSSMU2$

_SYSSMU3$

_SYSSMU4$

_SYSSMU5$

_SYSSMU6$

_SYSSMU7$

_SYSSMU8$

_SYSSMU9$

.........

alter system set "_corrupted_rollback_segments"='(_SYSSMU1$, _SYSSMU2$, _SYSSMU3$, _SYSSMU4$, _SYSSMU5$, _SYSSMU6$, _SYSSMU7$, _SYSSMU8$, _SYSSMU9$, _SYSSMU10$, _SYSSMU11$, _SYSSMU12$)' scope=spfile;

System altered.

/* 即便设置了_corrupted_rollback_segments隐式参数，也还有一定概率遭遇4000错误，尝试加上10513事件，并多次重启数据库 */

SQL> alter system set event='10513 trace name context forever,level 2' scope=spfile;

System altered.

/* 再次重启后发现4000错误不再出现 *

或者：undo_management 这是manual 

alter system set undo_management=manual ;

错误3

SQL>  recover database until cancel;

ORA-00283: recovery session canceled due to errors

ORA-16433: The database must be opened in read/write mode.

[oracle@yutianedu oracle]$ oerr  ora 16433

16433, 00000, "The database must be opened in read/write mode."

// *Cause:  An attempt was made to open the database in read-only mode after an

//          operation that requires that the database be opened in read/write

//          mode.

// *Action: Open the database in read/write mode. The database can then be

//          opened in read-only mode.

解决：重建控制文件

SQL> select name from v$datafile

NAME

--------------------------------------------------------------------------------

+DATA/orcl/datafile/system.256.853023133

+DATA/orcl/datafile/sysaux.257.853023133

+DATA/orcl/datafile/undotbs1.258.853023133

+DATA/orcl/datafile/users.259.853023133

+DATA/orcl/datafile/example.265.853023375

SQL> select group#,member from v$logfile

    GROUP# MEMBER

---------- ---------------------------------------------

         3 +DATA/orcl/onlinelog/group_3.263.853024583

         3 +FRA/orcl/onlinelog/group_3.259.853024593

         2 +DATA/orcl/onlinelog/group_2.262.853024563

         2 +FRA/orcl/onlinelog/group_2.258.853024575

         1 +DATA/orcl/onlinelog/group_1.261.853024541

         1 +FRA/orcl/onlinelog/group_1.257.853024555

         4 u01/app/oracle/redo401.log

         4 u01/app/oracle/redo402.log

8 rows selected.

 

重建控制文件语法：

SQL> select userenv('language') from dual;

USERENV('LANGUAGE')

----------------------------------------------------

AMERICAN_AMERICA.ZHS16GBK

cd home/oracle

vim c.sql 

CREATE CONTROLFILE REUSE DATABASE "ORCL" RESETLOGS  NOARCHIVELOG

         MAXLOGFILES 16

         MAXLOGMEMBERS 3

         MAXDATAFILES 100

        MAXINSTANCES 8

         MAXLOGHISTORY 292

    LOGFILE

       GROUP 1 ( '+DATA/orcl/onlinelog/group_1.261.853024541','+FRA/orcl/onlinelog/group_1.257.853024555')  SIZE 50M BLOCKSIZE 512,

       GROUP 2 ('+DATA/orcl/onlinelog/group_2.262.853024563','+FRA/orcl/onlinelog/group_2.258.853024575') SIZE 50M BLOCKSIZE 512,

      GROUP 3 ('+DATA/orcl/onlinelog/group_3.263.853024583','+FRA/orcl/onlinelog/group_3.259.853024593') SIZE 50M BLOCKSIZE 512,

GROUP 4 

('/u01/app/oracle/redo401.log','/u01/app/oracle/redo402.log') SIZE 50M BLOCKSIZE 512

DATAFILE

'+DATA/orcl/datafile/system.256.853023133',

'+DATA/orcl/datafile/sysaux.257.853023133',

'+DATA/orcl/datafile/undotbs1.258.853023133',

'+DATA/orcl/datafile/users.259.853023133',

'+DATA/orcl/datafile/example.265.853023375'

   CHARACTER SET ZHS16GBK

   ;

查出所有的控制文件 

SQL> select name from v$controlfile;

NAME

--------------------------------------------------------------------------------

+DATA/orcl/controlfile/current.260.853023315

+FRA/orcl/controlfile/current.256.853023315

shutdown immediate;

 

删除所有控制文件

su - grid

asmcmd

rm +DATA/orcl/controlfile/current.260.853023315

rm +FRA/orcl/controlfile/current.256.853023315

重建控制文件

sqlplus / as sysdba 

startup nomount 

@/home/oracle/c.sql 

SQL> select status from v$instance;

STATUS

------------

MOUNTED

开始开始进行recover：

 

recover database  until cancel;     #报错

recover database  until cancel using backup controlfile ;

cancel 

alter database open resetlogs;     #打开数据库

ORA-00603: ORACLE server session terminated by fatal error

ORA-00604: error occurred at recursive SQL level 1

ORA-01115: IO error reading block from file  (block # )

ORA-01110: data file 1: '+DATA/orcl/datafile/system.256.822001323'

ORA-15081: failed to submit an I/O operation to a disk

ORA-00604: error occurred at recursive SQL level 1

ORA-01115: IO error reading block from file  (block # )

ORA-01110: data file 1: '+DATA/orcl/datafile/system.256.822001323'

ORA-15081: failed to submit an I/O operation to a disk

ORA-01092: ORACLE instance terminated. Disconnection forced

ORA-00600: internal error code, arguments: [2662], [0], [1020724], [0],

[1025973], [12583040], [], [], [], [], [], []

Process ID: 29788

Session ID: 1 Serial number: 3

----------------------------------------------------------------------

exit 

sqlplus / as sysdba 

startup mount ;

alter session  set events '10015 trace name adjust_scn level 2';

shutdown immediate;

startup mount ;

alter database open ;

alter database open

*

ERROR at line 1:

ORA-01113: file 1 needs media recovery

ORA-01110: data file 1: '+DATA/orcl/datafile/system.256.822001323' 

系统核心文件 

没有备份 没归档，打不开数据库的  

要用工具au bbed 直接从数据文件中提取数据

最后alter database open resetlogs;

一定要备份（注意：系统表空间）