RMAN 下NOARCHIVELOG和ARCHIVE模式的恢復

恢復處於NOARCHIVELOG模式的數據庫

當數據庫處於NOARCHIVELOG模式時，若是出現介質故障 ，則最後一次備份以後對數據庫所作的任何操做都將丟失。經過RMAN執行恢復時，只須要執行restore命令將數據庫文件修復到正確的位置，而後就能夠打開數據庫。也就是說，對於處於NOARCHIVELOG模式下的數據庫，管理員不須要執行recover命令。

1.Sys登錄，並確認數據庫屬於NOARCHIVELOG模式

SQL> select log_mode from v$database;

 

LOG_MODE

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

ARCHIVELOG

 

SQL>

SQL>

SQL>

SQL> shutdown immediate

Database closed.

Database dismounted.

ORACLE instance shut down.

SQL> startup mount

ORACLE instance started.

 

Total System Global Area 2755870720 bytes

Fixed Size     2256432 bytes

Variable Size   671089104 bytes

Database Buffers  2063597568 bytes

Redo Buffers    18927616 bytes

Database mounted.

2.更改數據庫爲noarchivelog狀態

SQL> alter database noarchivelog;

alter database noarchivelog

*

ERROR at line 1:

ORA-38774: cannot disable media recovery - flashback database is enabled

 

 

SQL> alter database flashback off;

 

Database altered.

 

SQL> alter database noarchivelog;

 

Database altered.

 

SQL> archive log list;

 

 

 

3.執行一下命令，備份整個數據庫

RMAN> run{

2> allocate channel ch_1 type disk;

3> backup database

4> format '/u01/app/oracle/oradata/Backup/orcl_%t_%u.bak';

5> }

 

 

 

 

4.能夠查看一下備份下來的文件，上邊有路徑，數據文件和控制文件

 

 

 

5.模擬users.dbf丟失，這裏能夠先查找數據文件的位置

SQL> select file_name,tablespace_name,bytes from dba_data_files;

 

 

 

[oracle@orcl Backup]$ cd /u01/app/oracle/oradata/orcl

 

 

 

[oracle@orcl orcl]$ rm users01.dbf

 

 

 

6.刪除的時候數據庫必須是關閉的，否則系統禁止刪除正在使用的數據文件，如今到起庫測試一下，提示找不到數據文件

RMAN> startup

 

database is already started

RMAN-00571: ===========================================================

RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============

RMAN-00571: ===========================================================

RMAN-03002: failure of startup command at 12/04/2019 03:39:53

ORA-01157: cannot identify/lock data file 4 - see DBWR trace file

ORA-01110: data file 4: '/u01/app/oracle/oradata/orcl/users01.dbf'

 

RMAN> run{

7.startup mount狀態才能訪問數據文件，就能夠執行restore

RMAN> run{

2> allocate channel ch_1 type disk;

3> restore database;

4> }

 

 

 

這時候看一下數據文件是能夠恢復到目錄下的

 

 

 

8.起庫看一下是能夠起來的

RMAN> startup

 

database is already started

database opened

 

 

 

 

處於ARCHIVE模式

恢復處於archivelog模式的數據庫

1.查看數據庫是否處於歸檔

SQL> archive log list;

 

 

 

2.啓動rman對目標表空間進行備份，而後模擬刪除

[oracle@orcl Backup]$ ramn target /

RMAN> run{

2> allocate channel ch_1 type disk;

3> allocate channel ch_2 type disk;

4> backup tablespace users

5> format '/u01/app/oracle/oradata/Backup/users_tablespace.bak';

6> }

 

 

 

3.關閉數據庫，而後模擬刪除掉users.dbf，users.dbf的路徑怎麼找上邊寫的有命令

 

 

 

RMAN> shutdown immediate

 

database closed

database dismounted

Oracle instance shut down

 

RMAN> startup mount

 

RMAN> alter database open;

 

RMAN-00571: ===========================================================

RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============

RMAN-00571: ===========================================================

RMAN-03002: failure of alter db command at 12/04/2019 05:20:32

ORA-01157: cannot identify/lock data file 4 - see DBWR trace file

ORA-01110: data file 4: '/u01/app/oracle/oradata/orcl/users01.dbf'

 

4.數據庫如今mount狀態，恢復表空間

RMAN> run{

2> allocate channel ch_1 type disk;

3> restore tablespace users;      

4> recover tablespace users;

5> }

 

 

 

5.更改爲open狀態是沒有問題的，users的數據文件仍是在的

 

RMAN> alter database open;

 

database opened