Oracle备份&RMAN从零开始--fuzzy backup

A fuzzy backup is a secondary (or backup) copy of data file(s) or directories that were in one state when the backup started, but in a different state by the time the backup completed. This may result in the backup copy being unusable because of the . Although the backup process might have seemed successful, the resultant copies of the files or directories could be useless because a restore would yield inconsistent and unusable data.

模糊备份，是指对一个数据文件的拷贝。备份开始和结束是处于不同的状态，由于数据处于不一致状态可能导致文件不可用。虽然备份看起来可能是成功的。但是这样的备份可能导致不一致或者完全不可用的数据。

 

SQL> archive log list;
Database log mode              No Archive Mode
Automatic archival             Disabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     73
Current log sequence           75

SQL> conn test/test
Connected.

数据库运行过程中进行的拷贝。
SQL> !cp /oradata_2/oradata/tp_test.dbf tp_test.dbf.bak

进行创建表等操作
SQL> create table after_bak(aa varchar2(20));

Table created.
SQL> insert into after_bak values('test');

1 row created.

SQL> commit;

Commit complete.

关闭数据库，并恢复之前的备份后，重新打开数据库。

SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> !cp ~/tp_test.dbf.bak /oradata_2/oradata/tp_test.dbf

SQL> startup
ORACLE instance started.

Total System Global Area  285212672 bytes
Fixed Size                  1218968 bytes
Variable Size              75499112 bytes
Database Buffers          201326592 bytes
Redo Buffers                7168000 bytes
Database mounted.
ORA-01113: file 4 needs media recovery
ORA-01110: data file 4: '/oradata_2/oradata/tp_test.dbf'
注意，这里提示我们，第四个文件需要介质恢复。这个正是我们拷贝的数据文件tp_test.dbf.

SQL> recover
Media recovery complete.

SQL> alter database open;

Database altered.
SQL> select * from after_bak;

AA
--------------------
alert_orcl.log 内容：
WARNING! Recovering data file 4 from a fuzzy backup. It might be an online
backup taken without entering the begin backup command.