1、檢視資料庫基本資訊和資料庫狀態       
SQL> show parameter db_name


NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_name                              string      leonliao


SQL> show parameter control_files


NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
control_files                        string      /home/oracle/oradata/leonliao/
                                                 control01.ctl, /home/oracle/or
                                                 adata/leonliao/control02.ctl

SQL> select * from v$logfile;


    GROUP# STATUS  TYPE    MEMBER                                             IS_
---------- ------- ------- -------------------------------------------------- ---
         1         ONLINE  /home/oracle/oradata/leonliao/redo01.log           NO
         3         ONLINE  /home/oracle/oradata/leonliao/redo03.log           NO
         2         ONLINE  /home/oracle/oradata/leonliao/redo02.log           NO

SQL> select open_mode from v$database;


OPEN_MODE
--------------------
READ WRITE    


2、備份控制檔案
RMAN> backup current controlfile;     


3、資料庫線上時刪除所有控制檔案和redo檔案
[

[email protected] leonliao]$ rm -rf control0*ctl
[[email protected] leonliao]$ rm -rf redo0*log
[[email protected] leonliao]$ pwd
/home/oracle/oradata/leonliao

4、無法正常關閉資料庫只能shutdown abort
SQL> shutdown immediate
Database closed.
ORA-00210: cannot open the specified control file
ORA-00202: control file: '/home/oracle/oradata/leonliao/control01.ctl'
ORA-27041: unable to open file
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3

SQL> shutdown abort
ORACLE instance shut down.
SQL> 

5、啟動資料庫到nomount狀態並還原備份的控制檔案
SQL> startup nomount
ORACLE instance started.


Total System Global Area  626327552 bytes
Fixed Size                  2230952 bytes
Variable Size             184550744 bytes
Database Buffers          432013312 bytes
Redo Buffers                7532544 bytes


RMAN> restore controlfile from '/u01/app/oracle/dbs/01qvmtbj_1_1';


6、將資料庫啟動到mount狀態並生成建立控制檔案的指令碼
SQL> alter database mount;

Database altered.

SQL> alter database backup controlfile to trace;

Database altered.



7、shutdown immediate並啟動到startup nomount狀態建立resetlogs的控制檔案
SQL> shutdown immediate
ORA-01109: database not open
Database dismounted.
ORACLE instance shut down.
SQL> startup nomount
ORACLE instance started.


Total System Global Area  626327552 bytes
Fixed Size                  2230952 bytes
Variable Size             184550744 bytes
Database Buffers          432013312 bytes
Redo Buffers                7532544 bytes
SQL> CREATE CONTROLFILE REUSE DATABASE "LEONLIAO" RESETLOGS  ARCHIVELOG
  2      MAXLOGFILES 16
  3      MAXLOGMEMBERS 3
  4      MAXDATAFILES 100
  5      MAXINSTANCES 8
  6      MAXLOGHISTORY 292
  7  LOGFILE
  8    GROUP 1 '/home/oracle/oradata/leonliao/redo01.log'  SIZE 50M BLOCKSIZE 512,
  9    GROUP 2 '/home/oracle/oradata/leonliao/redo02.log'  SIZE 50M BLOCKSIZE 512,
 10    GROUP 3 '/home/oracle/oradata/leonliao/redo03.log'  SIZE 50M BLOCKSIZE 512
 11  -- STANDBY LOGFILE
 12  DATAFILE
 13    '/home/oracle/oradata/leonliao/system01.dbf',
 14    '/home/oracle/oradata/leonliao/sysaux01.dbf',
 15    '/home/oracle/oradata/leonliao/undotbs01.dbf',
 16    '/home/oracle/oradata/leonliao/users01.dbf'
 17  CHARACTER SET ZHS16GBK
 18  ;

Control file created.


8、因為所有redo檔案都刪除了，無法恢復，所以會出現一致性的問題，通過設定隱含引數_allow_resetlogs_corruption為true跳過一致性檢查；
SQL> alter system set "_allow_resetlogs_corruption"=true scope=spfile;

System altered.

SQL> shutdown immediate
ORA-01109: database not open
Database dismounted.
ORACLE instance shut down.

SQL> startup mount
ORACLE instance started.

Total System Global Area  626327552 bytes
Fixed Size                  2230952 bytes
Variable Size             184550744 bytes
Database Buffers          432013312 bytes
Redo Buffers                7532544 bytes
Database mounted.

9、以open resetlogs方式開啟資料庫
SQL> alter database open resetlogs;

Database altered.

SQL> select open_mode from v$database;

OPEN_MODE
--------------------
READ WRITE