1,rman可连接三种数据库
target database
recovery catalog database
auxiliary database
2,非catalog方式
  全备份,  0级增量备份， 1级增量备份
3,find / -name rman  
 用这个命令找一下根目录中的rman
如果linux中 /usr/.../bin/rman  在第一条，而/u01/oracle.../bin/rman在第二条
那条默认是linux的系统rman而不是oracle的rman,这个时候，可以去oracle的环境变量中，
  su 到oracle用户中， 然后用vi ./.bash_profile中，将PATH中的$PATH与

$ORACLE_HOME/PATH  进行互换，然后exit一下，再su到oracle用户中。 
用echo $PATH查看顺序。
4，确认database是archive log模式。
conn /as sysdba 进入到数据库中.
用 archive log list查看是不是archive mode 并且是enable状态
 如果是no archive log模式，可以将数据库start mount状态，然后alter database

archivelog  将数据库切到archive log 模式.
5,条件具备后，进入oracle用户，输入 rman nocatalog
  连接到target database  用  connect target / 命令连到target database
然后list backupset 命令查看是不是曾经备份过.
然后用backup database 全备数据库。
6，经过一段时间后，备份完成。
  进入ls /u01/flash_recovery_area..../backupset -lh查看一下

[root@oracle11g ~]# find / -name rman
/u01/oracle/bin/rman
/u01/oracle/sysman/admin/scripts/db/rman
/u01/oracle/oc4j/j2ee/oc4j_applications/applications/em/em/WEB-INF/perl/db/rman
[root@oracle11g ~]# su - oracle
[oracle@oracle11g ~]$ echo $path

[oracle@oracle11g ~]$ echo $PATH
/u01/oracle/bin:/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin:/u01/oracle/bin

[oracle@oracle11g ~]$ sqlplus /nolog

SQL*Plus: Release 11.2.0.1.0 Production on Sat Apr 14 19:52:05 2012

Copyright (c) 1982, 2009, Oracle.  All rights reserved.

SQL> conn   /as sysdba
Connected to an idle instance.
SQL> startup
ORACLE instance started.

Total System Global Area  619360256 bytes
Fixed Size                  1338280 bytes
Variable Size             394265688 bytes
Database Buffers          218103808 bytes
Redo Buffers                5652480 bytes
Database mounted.
Database opened.
SQL> archive log list
Database log mode              No Archive Mode
Automatic archival             Disabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     10
Current log sequence           12
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.

Total System Global Area  619360256 bytes
Fixed Size                  1338280 bytes
Variable Size             394265688 bytes
Database Buffers          218103808 bytes
Redo Buffers                5652480 bytes
Database mounted.
SQL> alter database archivelog
  2  ;

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     10
Next log sequence to archive   12
Current log sequence           12
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.

Total System Global Area  619360256 bytes
Fixed Size                  1338280 bytes
Variable Size             394265688 bytes
Database Buffers          218103808 bytes
Redo Buffers                5652480 bytes
Database mounted.
Database opened.
SQL> archive log list
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     10
Next log sequence to archive   12
Current log sequence           12
SQL> quit;
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
[oracle@oracle11g ~]$ rman

Recovery Manager: Release 11.2.0.1.0 - Production on Sat Apr 14 19:58:31 2012

Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

RMAN> quit

Recovery Manager complete.
[oracle@oracle11g ~]$ rman nocatalog

Recovery Manager: Release 11.2.0.1.0 - Production on Sat Apr 14 19:58:46 2012

Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

RMAN> list backupset;

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of list command at 04/14/2012 19:58:58
RMAN-06171: not connected to target database

RMAN> connect target /

connected to target database: SSM (DBID=1711362819)
using target database control file instead of recovery catalog

RMAN> list backupset;

specification does not match any backup in the repository

RMAN> backup database;

Starting backup at 14-APR-12
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=37 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=/u01/oradata/ssm/system01.dbf
input datafile file number=00002 name=/u01/oradata/ssm/sysaux01.dbf
input datafile file number=00005 name=/u01/oradata/ssm/example01.dbf
input datafile file number=00003 name=/u01/oradata/ssm/undotbs01.dbf
input datafile file number=00004 name=/u01/oradata/ssm/users01.dbf
channel ORA_DISK_1: starting piece 1 at 14-APR-12
channel ORA_DISK_1: finished piece 1 at 14-APR-12
piece handle=/u01/flash_recovery_area/SSM/backupset/2012_04_14/o1_mf_nnndf_TAG20120414T200131_7rn3yvvj_.bkp tag=TAG20120414T200131 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:04:16
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 14-APR-12
channel ORA_DISK_1: finished piece 1 at 14-APR-12
piece handle=/u01/flash_recovery_area/SSM/backupset/2012_04_14/o1_mf_ncsnf_TAG20120414T200131_7rn46z0y_.bkp tag=TAG20120414T200131 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 14-APR-12

RMAN> list backupset
2> ;

List of Backup Sets
===================

BS Key  Type LV Size       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
1       Full    1.03G      DISK        00:04:08     14-APR-12     
        BP Key: 1   Status: AVAILABLE  Compressed: NO  Tag: TAG20120414T200131
        Piece Name: /u01/flash_recovery_area/SSM/backupset/2012_04_14/o1_mf_nnndf_TAG20120414T200131_7rn3yvvj_.bkp
  List of Datafiles in backup set 1
  File LV Type Ckp SCN    Ckp Time  Name
  ---- -- ---- ---------- --------- ----
  1       Full 973546     14-APR-12 /u01/oradata/ssm/system01.dbf
  2       Full 973546     14-APR-12 /u01/oradata/ssm/sysaux01.dbf
  3       Full 973546     14-APR-12 /u01/oradata/ssm/undotbs01.dbf
  4       Full 973546     14-APR-12 /u01/oradata/ssm/users01.dbf
  5       Full 973546     14-APR-12 /u01/oradata/ssm/example01.dbf

BS Key  Type LV Size       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
2       Full    9.36M      DISK        00:00:04     14-APR-12     
        BP Key: 2   Status: AVAILABLE  Compressed: NO  Tag: TAG20120414T200131
        Piece Name: /u01/flash_recovery_area/SSM/backupset/2012_04_14/o1_mf_ncsnf_TAG20120414T200131_7rn46z0y_.bkp
  SPFILE Included: Modification time: 14-APR-12
  SPFILE db_unique_name: SSM
  Control File Included: Ckp SCN: 973642       Ckp time: 14-APR-12

RMAN> quit