将配置恢复目录的保留策略，然后备份该恢复目录。
1) 为 ORCL 数据库设置环境。
[oracle@rtest ~]$ export ORACLE_SID=test0924
2) 启动 RMAN，在不指定目录的情况下使用恢复目录数据库作为目标。
[oracle@rtest ~]$ rman target sys@rcat1028
Recovery Manager: Release 11.2.0.3.0 - Production on Mon Oct 28 16:17:22 2013
Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.
target database Password: ******
connected to target database: RCAT1028 (DBID=2744053659)
RMAN>
3) 确保已将恢复目录的保留策略设置为冗余大于 1 。如果该值不大于 1 ，则至少将其设置为 2 。
RMAN> show retention policy;
using target database control file instead of recovery catalog
RMAN configuration parameters for database with db_unique_name RCAT1028 are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default
RMAN> CONFIGURE RETENTION POLICY TO REDUNDANCY 2
2> ;
new RMAN configuration parameters:
CONFIGURE RETENTION POLICY TO REDUNDANCY 2;
new RMAN configuration parameters are successfully stored
4) 尝试备份数据库。
RMAN> backup database;
Starting backup at 28-OCT-13
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=190 device type=DISK
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
RMAN-03009: failure of backup command on ORA_DISK_1 channel at 10/28/2013 16:18:54
ORA-19602: cannot backup or copy active file in NOARCHIVELOG mode
continuing other job steps, job failed will not be re-run
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
including current control file in backup set
including current SPFILE in backup set
channel ORA_DISK_1: starting piece 1 at 28-OCT-13
channel ORA_DISK_1: finished piece 1 at 28-OCT-13
piece handle=+RECOVERY/rcat1028/backupset/2013_10_28/ncsnf0_tag20131028t161854_0.261.830017137 tag=TAG20131028T161854 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:04
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03009: failure of backup command on ORA_DISK_1 channel at 10/28/2013 16:18:54
ORA-19602: cannot backup or copy active file in NOARCHIVELOG mode
RMAN>
请注意，无法备份模式不为 ARCHIVELOG 的打开数据库。为确保最高的可用性，恢复目录数据库应以 ARCHIVELOG 模式运行。
5) 退出 RMAN。
RMAN> exit
6) 首先设置 RCAT1028数据库的环境，然后将恢复目录数据库更改为在 ARCHIVELOG 模式下运行。
[oracle@rtest dbs]$ export ORACLE_SID=rcat1028
[oracle@rtest dbs]$ sqlplus /nolog
SQL*Plus: Release 11.2.0.3.0 Production on Mon Oct 28 16:21:36 2013
Copyright (c) 1982, 2011, Oracle. All rights reserved.
SQL> conn /as sysdba
Connected.
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.
Total System Global Area 1235959808 bytes
Fixed Size 2227904 bytes
Variable Size 738197824 bytes
Database Buffers 486539264 bytes
Redo Buffers 8994816 bytes
Database mounted.
SQL> alter database archivelog;
Database altered.
SQL> alter database open;
Database altered.
SQL> archive log list;
Database log mode Archive Mode
Automatic archival Enabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 3
Next log sequence to archive 5
Current log sequence 5
SQL>
7) 确认RCAT1028数据库环境， 按照前面提供的步骤重新登录 RMAN。
[oracle@rtest ~]$ export ORACLE_SID=test0924
[oracle@rtest ~]$ rman target sys@rcat1028
Recovery Manager: Release 11.2.0.3.0 - Production on Mon Oct 28 16:25:17 2013
Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.
target database Password: ******
connected to target database: RCAT1028 (DBID=2744053659)
RMAN>
9) 备份恢复目录数据库。此时操作应成功。
RMAN> backup database;
Starting backup at 28-OCT-13
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=131 device type=DISK
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00001 name=+DATA/rcat1028/datafile/system.262.830015445
input datafile file number=00002 name=+DATA/rcat1028/datafile/sysaux.261.830015451
input datafile file number=00003 name=+DATA/rcat1028/datafile/undotbs1.265.830015451
input datafile file number=00005 name=+DATA/rcat01.dbf
input datafile file number=00004 name=+DATA/rcat1028/datafile/users.259.830015453
channel ORA_DISK_1: starting piece 1 at 28-OCT-13
channel ORA_DISK_1: finished piece 1 at 28-OCT-13
piece handle=+RECOVERY/rcat1028/backupset/2013_10_28/nnndf0_tag20131028t162544_0.262.830017545 tag=TAG20131028T162544 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:03:25
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
including current control file in backup set
including current SPFILE in backup set
channel ORA_DISK_1: starting piece 1 at 28-OCT-13
channel ORA_DISK_1: finished piece 1 at 28-OCT-13
piece handle=+RECOVERY/rcat1028/backupset/2013_10_28/ncsnf0_tag20131028t162544_0.263.830017753 tag=TAG20131028T162544 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:04
Finished backup at 28-OCT-13
RMAN> exit
Recovery Manager complete.
[oracle@rtest ~]$