在10g的时候 如果要将数据文件从os 迁移到asm 或者反之，必须使用rman或者dbms_file_transfer实现。在oracle 11g的asmcmd提供了cp命令来实现asm 磁盘组和os 之间，asm 磁盘之间的数据文件的迁移。
共如下三种方式：
1 .ASM Diskgroup to OS file system
2..OS file system to ASM Diskgroup
3 .ASM Diskgroup to another diskgroup
-- ASM Diskgroup to OS File system
ASMCMD [+data] > cp +DATA/rac/datafile/users.950.732883617 /tmp/user.dbf
copying +DATA/rac/datafile/users.950.732883617 -> /tmp/user.dbf
--OS File system to ASM Diskgroup
ASMCMD [+data] > cp /tmp/user.dbf +DATA/rac/datafile/users.950.732883617
copying /tmp/user.dbf -> +DATA/rac/datafile/users.950.732883617
--ASM Diskgroup to another diskgroup
SQL> create diskgroup dgext external redundancy disk '/dev/raw/raw1','/dev/raw/raw2';
Diskgroup created.
SQL> create diskgroup DGEXTBK external redundancy disk '/dev/raw/raw3','/dev/raw /raw4';
Diskgroup created.
ASMCMD> cd DGEXTBK
ASMCMD> mkdir prod
ASMCMD> cd prod
ASMCMD> mkdir datafile
ASMCMD> cd datafile
ASMCMD> pwd
+DGEXTBK/prod/datafile
SQL> create tablespace TBSEXT datafile '+DGEXT' size 10m;
Tablespace created.
SQL> select name from v$datafile;
NAME
-------------------------------------------------------------
+DGEXT/orcl/datafile/tbsext.256.628847401
ASMCMD> cp +DGEXT/orcl/datafile/tbsext.256.628847401 +DGEXTBK/prod/datafile/tbsext
+DGEXT/orcl/datafile/tbsext.256.628847401 -> +DGEXTBK/prod/datafile/tbsext
foldertbsext是建立在+DGEXTBK/prod/datafile文件夹下数据文件的别名，真正的文件建立在文件夹ASMTESTING下
ASMCMD> ls -ltr
Type Redund Striped Time Sys Name
N tbsext => +DGEXTBK/ASMTESTING/DATAFILE/TESTING.256.628848885
参考 metalink [ID 451900.1]
