Oracle恢复实验（一）

环境：Oracle10g、Red Hat 4，Oracle运行在归档模式。

模拟场景：user01.dbf数据文件损坏，关闭数据库条件下恢复。

具体步骤：

1、先做个全库冷备份，备份控制文件、数据文件、参数文件
SQL> select name from v$controlfile
  2  union
  3  select name from v$datafile;

NAME
--------------------------------------------------------------------------------
/home/oracle/oracle/product/oradata/orcl/control01.ctl
/home/oracle/oracle/product/oradata/orcl/control02.ctl
/home/oracle/oracle/product/oradata/orcl/control03.ctl
/home/oracle/oracle/product/oradata/orcl/sysaux01.dbf
/home/oracle/oracle/product/oradata/orcl/system01.dbf
/home/oracle/oracle/product/oradata/orcl/undotbs01.dbf
/home/oracle/oracle/product/oradata/orcl/users01.dbf

7 rows selected.

　也就是关库，备份上面几个文件，并且备份参数文件，口令文件可备可不备。

2、用scott用户登录，建个表，插入些数据。提交，检查一下数据行数。

SQL> conn scott/oracle
Connected.
SQL> create table recover_test tablespace users as select * from emp;

Table created.

SQL> insert into recover_test (select * from emp);

14 rows created.

SQL> insert into recover_test select * from recover_test;

56 rows created.

SQL> /

112 rows created.

SQL> /

224 rows created.

SQL> commit;

Commit complete.

SQL> select count (*) from recover_test;

  COUNT(*)
----------
       448
      
3、多做几次日志切换，这样有且于了解Oracle恢复的原理。
   
SQL> conn /as sysdba
Connected.
SQL> alter system switch logfile;

System altered.

SQL> /

System altered.

SQL> /

System altered.

SQL> /

System altered.

SQL> /

System altered.

SQL> /

System altered.

4、主机断电，删除user01.dbf，模拟数据文件损坏
SQL> shutdown abort
ORACLE instance shut down.
SQL> !rm -f /home/oracle/oracle/product/oradata/orcl/user01.dbf

5、尝试打开数据库
SQL> startup
ORACLE instance started.

Total System Global Area  130023424 bytes
Fixed Size                  1218100 bytes
Variable Size              62917068 bytes
Database Buffers           62914560 bytes
Redo Buffers                2973696 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 4 - see DBWR trace file
ORA-01110: data file 4: '/home/oracle/oracle/product/oradata/orcl/users01.dbf'

此时提示数据文件找不到。警告日志中可以看到更加详细的信息。

6、恢复数据文件，尝试打开数据库
SQL> !cp /disk2/bak/users01.dbf /home/oracle/oracle/product/oradata/orcl/

SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-01113: file 4 needs media recovery
ORA-01110: data file 4: '/home/oracle/oracle/product/oradata/orcl/users01.dbf'

此时由于数据库不一致，提示需要介质恢复。检查一下scn情况。
select 'scnOfDatafile',name,checkpoint_change# from v$datafile
union
select 'scnOfDatafileHeader',name,checkpoint_change# from v$datafile_header;

'SCNOFDATAFILE'     NAME                                    &nbs