在ORACLE 10G/11G版本时，如果要将数据库的数据文件，移动到不同的磁盘目录（即修改磁盘路径），如果数据库在OPEN状态需要将数据文件OFFLINE，或者在数据库MOUNT状态下进行修补。
在12C及以上版本时，可以在线移动一个正在被访问的数据文件；即是system表空间中的数据文件也可以。
可以在线移动数据文件，表示当用户正在访问系统的时候，很多维护操作可以在线执行；例如，将数据文件移动到其他存储设备或者移动到Oracle ASM。这确保了服务的连续性，并且满足正常运行时的服务水平协议（SLA）。
在 12C，当数据文件处于在线状态并且正在被访问的时候，可以执行下面的操作： 1. 重命名在线数据库文件 2. 迁移在线数据库文件 3. 拷贝在线数据文件 4. 迁移在线数据文件并且覆盖现有文件 5. 迁移在线数据文件到 oracle ASM
如下为对这些功能的测试案例：
1.在线移动数据文件-文件系统-ASM
–可用于数据文件重命令、从一个目录移动到另一目录(可能涉及不同的磁盘或分区、LV)
–直接使用MOVE DATAFILE参数相当于是移动或者重命令，不会保留原数据文件
–keep关键字，可以实现拷贝数据文件到新位置，原文件保留
移动PDB中数据文件需要在指定 的PDB中进行操作：
show con_name
CON_NAME
——————————
CDBPDB2
C##Luda@cdbpdb2>select name from v$dbfile;
NAME
————————————————————————————————————————————————————————————
/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/4FDB7936712F5A06E053D339A8C06FAC/datafile/o1_mf_sysaux_dkx3hppr_.dbf
/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/4FDB7936712F5A06E053D339A8C06FAC/datafile/o1_mf_undotbs1_dkx3hppt_.dbf
/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/4FDB7936712F5A06E053D339A8C06FAC/datafile/o1_mf_pdb2_dkx9pq4r_.dbf
/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/system01.dbf
C##Luda@cdbpdb2>alter database MOVE DATAFILE ‘/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/4FDB7936712F5A06E053D339A8C06FAC/datafile/o1_mf_sysaux_dkx3hppr_.dbf’ to ‘/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/sysaux01.dbf’;
Database altered.
C##Luda@cdbpdb2>!ls /u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/4FDB7936712F5A06E053D339A8C06FAC/datafile/o1_mf_sysaux_dkx3hppr_.dbf
ls: cannot access /u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/4FDB7936712F5A06E053D339A8C06FAC/datafile/o1_mf_sysaux_dkx3hppr_.dbf: No such file or directory
C##Luda@cdbpdb2>!ls /u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/sysaux01.dbf
/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/sysaux01.dbf
C##Luda@cdbpdb2>select file_name, status, online_status from dba_data_files;
FILE_NAME STATUS ONLINE_
——————————————————————————– ——— ——-
/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/sysaux01.dbf AVAILABLE ONLINE
/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/4FDB7936712F5A06E053D339A8C06FA AVAILABLE ONLINE
C/datafile/o1_mf_undotbs1_dkx3hppt_.dbf
/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/4FDB7936712F5A06E053D339A8C06FA AVAILABLE ONLINE
C/datafile/o1_mf_pdb2_dkx9pq4r_.dbf
/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/system01.dbf AVAILABLE SYSTEM
观察此时的ALERT日志：
2017-05-23T14:43:17.122383+08:00
CDBPDB2(4):alter database MOVE DATAFILE ‘/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/4FDB7936712F5A06E053D339A8C06FAC/datafile/o1_mf_sysaux_dkx3hppr_.dbf’ to ‘/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/sysaux01.dbf’
2017-05-23T14:43:17.146362+08:00
Moving datafile /u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/4FDB7936712F5A06E053D339A8C06FAC/datafile/o1_mf_sysaux_dkx3hppr_.dbf (22) to /u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/sysaux01.dbf
2017-05-23T14:43:55.724994+08:00
Move operation committed for file /u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/sysaux01.dbf
2017-05-23T14:43:58.166391+08:00
CDBPDB2(4):Completed: alter database MOVE DATAFILE ‘/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/4FDB7936712F5A06E053D339A8C06FAC/datafile/o1_mf_sysaux_dkx3hppr_.dbf’ to ‘/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/sysaux01.dbf’
使用KEEP关键字的测试：–OMF管理的不会保留原文件，
C##Luda@cdbpdb2>alter database MOVE DATAFILE ‘/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/4FDB7936712F5A06E053D339A8C06FAC/datafile/o1_mf_pdb2_dkx9pq4r_.dbf’ to ‘/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/pdb201.dbf’ keep;
Database altered.
C##Luda@cdbpdb2>select file_name, status, online_status from dba_data_files;
FILE_NAME STATUS ONLINE_
——————————————————————————– ——— ——-
/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/sysaux01.dbf AVAILABLE ONLINE
/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/pdb201.dbf AVAILABLE ONLINE
/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/4FDB7936712F5A06E053D339A8C06FA AVAILABLE ONLINE
C/datafile/o1_mf_undotbs1_dkx3hppt_.dbf
/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/system01.dbf AVAILABLE SYSTEM
C##Luda@cdbpdb2>!ls /u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/4FDB7936712F5A06E053D339A8C06FAC/datafile/o1_mf_pdb2_dkx9pq4r_.dbf
ls: cannot access /u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/4FDB7936712F5A06E053D339A8C06FAC/datafile/o1_mf_pdb2_dkx9pq4r_.dbf: No such file or directory
C##Luda@cdbpdb2>!ls /u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/pdb201.dbf
/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/pdb201.dbf
C##Luda@cdbpdb2>alter database MOVE DATAFILE ‘/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/pdb201.dbf’ to ‘/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/pdb201.dbf’ keep;
Database altered.
C##Luda@cdbpdb2>!ls /u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/pdb201.dbf
/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/pdb201.dbf
C##Luda@cdbpdb2>!ls /u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/pdb201.dbf
/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/pdb201.dbf
使用REUSE关键字覆盖
C##Luda@cdbpdb2>!ls /u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/pdb201.dbf
/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/pdb201.dbf
C##Luda@cdbpdb2>!ls /u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/pdb201.dbf
/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/pdb201.dbf
C##Luda@cdbpdb2>alter database MOVE DATAFILE ‘/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/pdb201.dbf’ to ‘/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/pdb201.dbf’ keep;
alter database MOVE DATAFILE ‘/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/pdb201.dbf’ to ‘/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/pdb201.dbf’ keep
*
ERROR at line 1:
ORA-01119: error in creating database file ‘/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/pdb201.dbf’
ORA-27038: created file already exists
Additional information: 1
C##Luda@cdbpdb2>alter database MOVE DATAFILE ‘/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/pdb201.dbf’ to ‘/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/pdb201.dbf’ reuse;
C##Luda@cdbpdb2>!ls /u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/pdb201.dbf
ls: cannot access /u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/LudaCDB/pdb201.dbf: No such file or directory
C##Luda@cdbpdb2>!ls /u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/pdb201.dbf
/u01/app/oracle12c/oradata/Ludacdb/cdbpdb2/pdb201.dbf
