Oracle的RMAN配置信息默认存放在target数据库的控制文件中，当然也可以配置一个recovery catalog服务器来存储这些信息，下面是控制文件和恢复的特性比较，一般来说维护10台以下的oracle数据库备份，可以不需要配置恢复目录.
Control file:
– Simpler administration
– Default
Recovery catalog:
– Replicates control file data
– Has room for more data
– Can service many targets
– Can store RMAN scripts
RMAN repository data is always stored in the control file of the target database. But it can also be stored in a separate database, called a recovery catalog.
A recovery catalog preserves backup information in a separate database, which is useful in the event of a lost control file. This allows you to store a longer history of backups than what is possible with a control file–based repository. A single recovery catalog is able to store information for multiple target databases. The recovery catalog can also hold RMAN stored scripts, which are sequences of RMAN commands for common backup tasks. Centralized storage of scripts in the recovery catalog can be more convenient than working with command files.
Usage of a separate recovery catalog database is not recommended for small installations where administration of a separate recovery catalog database would be burdensome
下面来演示下恢复目录的配置，其中ora10g为catalog数据库，target数据库为orac
1:创建用户和表空间并授权
SQL> CREATE TABLESPACE rman DATAFILE '/u01/app/oradata/rman01.dbf'
2 SIZE 500M AUTOEXTEND ON NEXT 20M MAXSIZE 2G EXTENT MANAGEMENT LOCAL;
Tablespace created.
SQL> CREATE USER RMAN IDENTIFIED BY rman
2 TEMPORARY TABLESPACE temp
3 DEFAULT TABLESPACE rman
4 QUOTA UNLIMITED ON rman;
User created.
SQL> GRANT RECOVERY_CATALOG_OWNER TO rman;
Grant succeeded.
SQL> conn rman/rman
Connected.
SQL> select count (*) from user_objects;
COUNT(*)
----------
0
2：创建恢复目录
[oracle@ora10g ~]$ rman catalog rman/rman@ora10g
Recovery Manager: Release 10.2.0.1.0 - Production on Wed Mar 16 09:58:16 2011
Copyright (c) 1982, 2005, Oracle. All rights reserved.
connected to recovery catalog database
RMAN> CREATE CATALOG;
recovery catalog created
SQL> select count (*) from user_objects; //可以看出在rman表空间下的对象个数为195个
COUNT(*)
----------
195
3：连接,注册目标数据库，同步catalog和控制文件
[oracle@orac ~]$ rman target sys/123456@orac catalog rman/rman@ora10g
Recovery Manager: Release 10.2.0.1.0 - Production on Wed Mar 16 10:14:10 2011
Copyright (c) 1982, 2005, Oracle. All rights reserved.
connected to target database: ORAC (DBID=1010679485)
connected to recovery catalog database
RMAN> REGISTER DATABASE;
database registered in recovery catalog
starting full resync of recovery catalog
full resync complete
RMAN> RESYNC CATALOG;
starting full resync of recovery catalog
full resync complete
RMAN> LIST INCARNATION;
List of Database Incarnations
DB Key Inc Key DB Name DB ID STATUS Reset SCN Reset Time
------- ------- -------- ---------------- --- ---------- ----------
1 8 ORAC 1010679485 PARENT 1 22-OCT-05
1 2 ORAC 1010679485 CURRENT 525876 15-FEB-11