Oracle备份/恢复案例02--文件恢复
一、非归档模式下的备份与恢复
备份方案：采用OS冷备份
1、连接数据库并创建测试表
SQL*Plus: Release 9.2.0.1.0 - Production on Tue Jan 13 10:03:27 2009
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
SQL> connect sys/sys as sysdba;
Connected.
SQL> create table test(a int) tablespace users;
Table created
SQL> insert into test values(1);
1 row inserted
SQL> commit;
Commit complete
Connected.
SQL> create table test(a int) tablespace users;
Table created
SQL> insert into test values(1);
1 row inserted
SQL> commit;
Commit complete
2、备份数据库
SQL> @ D:\test\coldbak.sql
3、再插入记录
SQL> insert into test values(2);
1 row inserted
SQL> commit;
Commit complete
SQL> select * from test;
A
------------------------
1
2
4、关闭数据库
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
5 、毁坏一个或多个数据文件，如删除user01.dbf
C:> del D:\ORACLE\ORADATA\DODO\USERS01.DBF
6、重新启动数据库， Oracle报错
SQL> startup
ORACLE instance started.
Total System Global Area 135338868 bytes
Fixed Size 453492 bytes
Variable Size 109051904 bytes
Database Buffers 25165824 bytes
Redo Buffers 667648 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 6 - see DBWR trace file
ORA-01110: data file 6: 'D:\ORACLE\ORADATA\DODO\USERS01.DBF'
Fixed Size 453492 bytes
Variable Size 109051904 bytes
Database Buffers 25165824 bytes
Redo Buffers 667648 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 6 - see DBWR trace file
ORA-01110: data file 6: 'D:\ORACLE\ORADATA\DODO\USERS01.DBF'
在报警文件中，会有更详细的信息
Errors in file d:\oracle\admin\dodo\bdump\dodo_dbw0_3648.trc:
ORA-01157: cannot identify/lock data file 6 - see DBWR trace file
ORA-01110: data file 6: 'D:\ORACLE\ORADATA\DODO\USERS01.DBF'
ORA-27041: unable to open file
OSD-04002: 无法打开文件
O/S-Error: (OS 2) 系统找不到指定的文件。
7、拷贝备份复原到原来位置(restore过程)
C:> xcopy D:\DATABASE\BACK \USERS01.DBF D:\ORACLE\ORADATA\DODO /H/R/S
8、打开数据库，检查数据
SQL> alter database open;
Database altered.
SQL> select * from test;
A
------------------------
1
这里可以发现，数据库恢复成功，但在备份之后与崩溃之前的数据丢失了。
说明：
1、非归档模式下的恢复方案可选性很小，一般情况下只能有一种恢复方式，就是数据库的冷备份的完全恢复。仅仅需要 拷贝原来的备份就可以(restore)，不需要recover。
2、这种情况下的恢复，可以完全恢复到备份的点上，但是可能是丢失数据的，在备份之后与崩溃之前的数据将全部丢失。
3、不管毁坏了多少数据文件或是联机日志或是控制文件，都可以通过这个办法恢复，因为这个恢复过程是Restore所有的冷备份文件，而这个备份点上的所有文件是一致的，与最新的数据库没有关系，就好比把数据库又放到了一个以前的“点”上。
4、对于非归档模式下，最好的办法就是采用OS的冷备份，建议不要用RMAN来作冷备份，效果不好，因为 RMAN不备份联机日志，restore不能根本解决问题。
5、如果没有备份联机日志，如RMAN的备份，就需要利用不完全恢复(until cancel)的方法来重新创建联机日志文件。
二、归档模式下丢失或损坏一个数据文件
1.
OS备份方案
在归档方式下损坏或丢失一个数据文件，如果存在相应的备份与该备份以来的归档日志，恢复还是比较简单的，可以作到尽量少的Down机时间，并能作到数据库的完全恢复。
1、连接数据库，创建测试表并插入记录
SQL*Plus: Release 9.2.0.1.0 - Production on Tue Jan 13 10:03:27 2009
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
SQL> connect sys/sys as sysdba;
Connected.
SQL> create table test(a int) tablespace users;
Table created
SQL> insert into test values(1);
1 row inserted
SQL> commit;
Commit complete
Connected.
SQL> create table test(a int) tablespace users;
Table created
SQL> insert into test values(1);
1 row inserted
SQL> commit;
Commit complete
2、备份数据库
SQL> @ D:\test\hotbak.sql
3、继续在测试表中插入记录
SQL> insert into test values(2);
1 row inserted
SQL> commit;
Commit complete
SQL> select * from test;
A
---------------------------------------
1
2
SQL> alter system switch logfile;
System altered.
SQL> alter system switch logfile;
System altered.
4、关闭数据库，模拟丢失数据文件
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down
C:> del D:\ORACLE\ORADATA\DODO\USERS01.DBF
5、启动数据库错误，脱机该数据文件
SQL> startup
ORACLE instance started.
Total System Global Area 135338868 bytes
Fixed Size 453492 bytes
Variable Size 109051904 bytes
Database Buffers 25165824 bytes
Redo Buffers 667648 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 6 - see DBWR trace file
ORA-01110: data file 6: 'D:\ORACLE\ORADATA\DODO\USERS01.DBF'
Fixed Size 453492 bytes
Variable Size 109051904 bytes
Database Buffers 25165824 bytes
Redo Buffers 667648 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 6 - see DBWR trace file
ORA-01110: data file 6: 'D:\ORACLE\ORADATA\DODO\USERS01.DBF'
还可以查看报警文件 (见上一个恢复案例 )或动态视图v$recover_file
idle> select * from v$recover_file;
FILE# ONLINE ONLINE_ ERROR CHANGE# TIME
---------- ------- ------- -------------------- ---------- ----------
6 ONLINE ONLINE FILE NOT FOUND 0
---------- ------- ------- -------------------- ---------- ----------
6 ONLINE ONLINE FILE NOT FOUND 0
脱机数据文件 :
SQL> alter database datafile 6 offline drop;
Database altered.
6、打开数据库，拷贝备份回来(restore)，恢复(recover)该数据文件，并联机
打开数据库：
SQL> alter database open;
Database altered.
拷贝备份从备份处
C:> xcopy D:\DATABASE\BACK \USERS01.DBF D:\ORACLE\ORADATA\DODO /H/R/S
Database altered.
拷贝备份从备份处
C:> xcopy D:\DATABASE\BACK \USERS01.DBF D:\ORACLE\ORADATA\DODO /H/R/S
恢复该数据文件
SQL> recover datafile 6;
Media recovery complete.
恢复成功，联机该数据文件 :
SQL> alter database datafile 6 online;
Database altered.
7、检查数据库的数据 (完全恢复 )
SQL> select * from test;
A
--------------------------
1
2
说明：
1、采用热备份，需要运行在归档模式下，可以实现数据库的完全恢复，也就是说，从备份后到数据库崩溃时的数据都不会丢失。
2、可以采用全备份数据库的方式备份，对于特殊情况，也可以只备份特定的数据文件，如只备份用户表空间 (一般情况下对于某些写特别频繁的数据文件，可以单独加大备份频率 )
3、如果在恢复过程中，发现损坏的是多个数据文件，即可以采用一个一个数据文件的恢复方法 (第5步中需要对数据文件一一脱机，第6步中需要对数据文件分别恢复 )，也可以采用整个数据库的恢复方法。
4、如果是系统表空间的损坏，不能采用此方法
2、可以采用全备份数据库的方式备份，对于特殊情况，也可以只备份特定的数据文件，如只备份用户表空间 (一般情况下对于某些写特别频繁的数据文件，可以单独加大备份频率 )
3、如果在恢复过程中，发现损坏的是多个数据文件，即可以采用一个一个数据文件的恢复方法 (第5步中需要对数据文件一一脱机，第6步中需要对数据文件分别恢复 )，也可以采用整个数据库的恢复方法。
4、如果是系统表空间的损坏，不能采用此方法
2. RMAN备份方案
RMAN也可以进行联机备份，而且备份与恢复方法将比OS备份更简单可靠。
1、连接数据库，创建测试表并插入记录
SQL*Plus: Release 9.2.0.1.0 - Production on Tue Jan 13 10:03:27 2009
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
SQL> connect sys/sys as sysdba;
Connected.
SQL> create table test(a int) tablespace users;
Table created
SQL> insert into test values(1);
1 row inserted
SQL> commit;
Commit complete
Connected.
SQL> create table test(a int) tablespace users;
Table created
SQL> insert into test values(1);
1 row inserted
SQL> commit;
Commit complete
2、备份数据库表空间users
C:> rman
Recovery Manager: Release 9.2.0.1.0 - Production
Copyright (c) 1995, 2002, Oracle Corporation. All rights reserved.
RMAN> connect rcvcat rman/rman
RMAN> connect rcvcat rman/rman
connected to recovery catalog database
RMAN> connect target sys/sys
connected to target database: DODO (DBID=472976704)
RMAN> connect target sys/sys
connected to target database: DODO (DBID=472976704)
RMAN> run{
2> allocate channel c1 type disk;
3> backup tag 'tsuser' format 'D:\DATABASE\RMAN \tsuser_%u_%s_%p' ;
4> tablespace users;
5> release channel c1;
6> }
2> allocate channel c1 type disk;
3> backup tag 'tsuser' format 'D:\DATABASE\RMAN \tsuser_%u_%s_%p' ;
4> tablespace users;
5> release channel c1;
6> }
allocated channel: c1
channel c1: sid=18 devtype=DISK
Starting backup at 2009-01-13
channel c1: starting full datafile backupset
channel c1: specifying datafile(s) in backupset
input datafile fno=00006 name=D:\ORACLE\ORADATA\DODO\USERS01.DBF
channel c1: starting piece 1 at 2009-01-13
channel c1: finished piece 1 at 2009-01-13
piece handle=D:\DATABASE\RMAN\TSUSER_1NK4MUKK_55_1 comment=NONE
channel c1: backup set complete, elapsed time: 00:00:35
Finished backup at 2009-01-13
channel c1: starting full datafile backupset
channel c1: specifying datafile(s) in backupset
input datafile fno=00006 name=D:\ORACLE\ORADATA\DODO\USERS01.DBF
channel c1: starting piece 1 at 2009-01-13
channel c1: finished piece 1 at 2009-01-13
piece handle=D:\DATABASE\RMAN\TSUSER_1NK4MUKK_55_1 comment=NONE
channel c1: backup set complete, elapsed time: 00:00:35
Finished backup at 2009-01-13
Starting Control File and SPFILE Autobackup at 2009-01-13
piece handle=D:\ORACLE\ORADATA\DODO\RMANBACK\CTL_C-472976704-20090113-01 comment=NONE
Finished Control File and SPFILE Autobackup at 2009-01-13
piece handle=D:\ORACLE\ORADATA\DODO\RMANBACK\CTL_C-472976704-20090113-01 comment=NONE
Finished Control File and SPFILE Autobackup at 2009-01-13
released channel: c1
3、继续在测试表中插入记录
SQL> insert into test values(2);
1 row inserted
SQL> commit;
Commit complete
SQL> select * from test;
A
---------------------------------
1
2
SQL> alter system switch logfile;
System altered.
SQL> r
1* alter system switch logfile;
System altered.
4、关闭数据库，模拟丢失数据文件
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down
C:> del D:\ORACLE\ORADATA\DODO\USERS01.DBF
5、启动数据库，检查错误
SQL> startup
ORACLE instance started.
Total System Global Area 135338868 bytes
Fixed Size 453492 bytes
Variable Size 109051904 bytes
Database Buffers 25165824 bytes
Redo Buffers 667648 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 6 - see DBWR trace file
ORA-01110: data file 6: 'D:\ORACLE\ORADATA\DODO\USERS01.DBF'
Fixed Size 453492 bytes
Variable Size 109051904 bytes
Database Buffers 25165824 bytes
Redo Buffers 667648 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 6 - see DBWR trace file
ORA-01110: data file 6: 'D:\ORACLE\ORADATA\DODO\USERS01.DBF'
6、先打开数据库
SQL> alter database datafile 6 offline drop;
Database altered.
SQL> alter database open;
Database altered.
7、恢复该表空间
恢复脚本可以是恢复单个数据文件
run{
allocate channel c1 type disk;
restore datafile 3;
recover datafile 3;
sql 'alter database datafile 3 online';
release channel c1;
}
也可以是,恢复表空间
run{
allocate channel c1 type disk;
restore tablespace users;
recover tablespace users;
sql 'alter database datafile 3 online';
release channel c1;
}
过程如下：
C:> rman
Recovery Manager: Release 9.2.0.1.0 - Production
Copyright (c) 1995, 2002, Oracle Corporation. All rights reserved.
RMAN> connect rcvcat rman/rman
RMAN> connect rcvcat rman/rman
connected to recovery catalog database
RMAN> connect target sys/sys
connected to target database: DODO (DBID=472976704)
RMAN> connect target sys/sys
connected to target database: DODO (DBID=472976704)
RMAN> run{
2> allocate channel c1 type disk;
3> restore datafile 6;
4> recover datafile 6;
5> sql 'alter database datafile 6 online';
6> release channel c1;
7> }
allocated channel: c1
channel c1: sid=18 devtype=DISK
Starting restore at 2009-01-13
channel c1: starting datafile backupset restore
channel c1: specifying datafile(s) to restore from backup set
restoring datafile 00006 to D:\ORACLE\ORADATA\DODO\USERS01.DBF
channel c1: restored backup piece 1
piece handle=D:\DATABASE\RMAN\TSUSER_1NK4MUKK_55_1 tag=TSUSER params=NULL
channel c1: restore complete
Finished restore at 2009-01-13
channel c1: specifying datafile(s) to restore from backup set
restoring datafile 00006 to D:\ORACLE\ORADATA\DODO\USERS01.DBF
channel c1: restored backup piece 1
piece handle=D:\DATABASE\RMAN\TSUSER_1NK4MUKK_55_1 tag=TSUSER params=NULL
channel c1: restore complete
Finished restore at 2009-01-13
Starting recover at 2009-01-13
starting media recovery
media recovery complete
media recovery complete
Finished recover at 2009-01-13
sql statement: alter database datafile 6 online
released channel: c1
8、检查数据是否完整
SQL> select * from test;
A
--------------------------------
1
2
说明：
1、RMAN也可以实现单个表空间或数据文件的恢复，恢复过程可以在mount下或open方式下，如果在open方式下恢复，可以减少down机时间
2、如果损坏的是一个数据文件，建议offline并在open方式下恢复
3、这里可以看到，RMAN进行数据文件与表空间恢复的时候，代码都比较简单，而且能保证备份与恢复的可靠性，所以建议采用RMAN的备份与恢复
2、如果损坏的是一个数据文件，建议offline并在open方式下恢复
3、这里可以看到，RMAN进行数据文件与表空间恢复的时候，代码都比较简单，而且能保证备份与恢复的可靠性，所以建议采用RMAN的备份与恢复
-The End-