1,请参上一节，我所述关于利用rman tool to create dg standby示例
2,唯一不同的，请在最终rman脚本上，添加如下，或者：修正如下：
  run
{--set until scn scn号；--源于主库的select max(next_change#) from v$database;
   duplicate target database for standby
   nofilenamecheck
   dorecover;
}

3,在主库生成备库控制文件，一定要采用如下脚本  --此步太重要，我就是因为此步，花一大下午的时间，最终是三思大指导，处结此事，在些感谢三思大师指点！！
    startup mount
     copy current controlfile for standby to '控制文件备份路径';
     sql 'alter database open';
     sql 'alter system archive log current';


4,附上我出错的相关错误，供备记：
RMAN> run
2> {set until scn 693020;
3> duplicate target database for standby
4> nofilenamecheck
5> dorecover;
6> }

executing command: SET until clause
using target database control file instead of recovery catalog

Starting Duplicate Db at 31-JAN-10
allocated channel: ORA_AUX_DISK_1
channel ORA_AUX_DISK_1: sid=156 devtype=DISK

contents of Memory Script.:
{
   set until scn  693020;
   restore clone standby controlfile;
   sql clone 'alter database mount standby database';
}
executing Memory Script

executing command: SET until clause

Starting restore at 31-JAN-10
using channel ORA_AUX_DISK_1

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of Duplicate Db command at 01/31/2010 03:20:21
RMAN-03015: error occurred in stored script. Memory Script
RMAN-06026: some targets not found - aborting restore
RMAN-06024: no backup or copy of the control file found to restore