虚拟机在不通RHEV平台上的迁移，其实就是虚拟机的导入和导出，关于如何在Data Center之间导出导入虚拟机，请参考以下步骤：
To export individual virtual machines to the export domain:
~~~
1.Click the Virtual Machines tab.
2.If the virtual machine you want toexport is not visible in the list, perform a search.
3.Select the virtual machine.
4.Shut down the virtual machine. Oncethe virtual machine is shut down, right click to display the menu.
5.Click the Export option.
6.The Export Virtual Machine dialog boxdisplays. Select from the list of available options as appropriate, ForceOverride and Collapse Snapshots.
Select Force Override to overrideexisting p_w_picpaths of the virtual machine which may already exist on the exportdomain.
Select Collapse Snapshots to create asingle export file per disk. Select this option if you wish to retain both thesource and destination versions of the virtual machine.
7.Click OK.
The export of the virtual machinebegins, this can take some time. The virtual machine displays in the VirtualMachines list with a Locked Status. Use the Events tab to view the progress.
8.The Events tab displays that thevirtual machine has been exported.
9.The virtual machine displays on the VMImport tab of the export domain.
10.You can repeat the procedure above toexport each virtual machine that you need to migrate, so that the export domainhas a number of virtual machines.
~~~
To Import the Virtual Machine into the Destination Data Center:
~~~
1.Detach the export domain from thesource data center, then attach it to the destination data center.
2.On the Storage tab, select the Exportdata domain. The Details pane of the Export storage domain displays.
3.On the Details pane, select the VMImport tab. Select the virtual machine that is to be imported. Click Import.
4.The Import Virtual Machine dialog boxdisplays. The names of the available virtual machines display.
5.Select the name of the virtualmachine, and select the Destination Cluster and Destination Storage of thedestination data center.
6.If you have not deleted the originalvirtual machine in the source data center, select Collapse Snapshots.
7.Click OK. The virtual machine isimported into the destination data center. This can take some time. Eventually,the virtual machine displays in the Virtual Machines tab on the Details pane ofthe Storage domain belonging to the destination data center.
8.You can now run the virtual machine,provided that the virtual machine was created from scratch, or from a templatewhich still resides in the storage domain.
~~~
也可参考RHEV3.3的《Administration Guide》的7.7.Storage Tasks部分。
https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Virtualization/3.3/html-single/Administration_Guide/index.html#sect-Storage_Tasks