RMAN 下NOARCHIVELOG和ARCHIVE模式的恢复

恢复处于NOARCHIVELOG模式的数据库

当数据库处于NOARCHIVELOG模式时，若是出现介质故障 ，则最后一次备份以后对数据库所作的任何操做都将丢失。经过RMAN执行恢复时，只须要执行restore命令将数据库文件修复到正确的位置，而后就能够打开数据库。也就是说，对于处于NOARCHIVELOG模式下的数据库，管理员不须要执行recover命令。

1.Sys登录，并确认数据库属于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.更改数据库为noarchivelog状态

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.执行一下命令，备份整个数据库

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.能够查看一下备份下来的文件，上边有路径，数据文件和控制文件

 

 

 

5.模拟users.dbf丢失，这里能够先查找数据文件的位置

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.删除的时候数据库必须是关闭的，否则系统禁止删除正在使用的数据文件，如今到起库测试一下，提示找不到数据文件

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状态才能访问数据文件，就能够执行restore

RMAN> run{

2> allocate channel ch_1 type disk;

3> restore database;

4> }

 

 

 

这时候看一下数据文件是能够恢复到目录下的

 

 

 

8.起库看一下是能够起来的

RMAN> startup

 

database is already started

database opened

 

 

 

 

处于ARCHIVE模式

恢复处于archivelog模式的数据库

1.查看数据库是否处于归档

SQL> archive log list;

 

 

 

2.启动rman对目标表空间进行备份，而后模拟删除

[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.关闭数据库，而后模拟删除掉users.dbf，users.dbf的路径怎么找上边写的有命令

 

 

 

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.数据库如今mount状态，恢复表空间

RMAN> run{

2> allocate channel ch_1 type disk;

3> restore tablespace users;      

4> recover tablespace users;

5> }

 

 

 

5.更改为open状态是没有问题的，users的数据文件仍是在的

 

RMAN> alter database open;

 

database opened