Importing and exporting virtual machines
XenServer allows you to import VMs from and export them to a number of different formats. Using the XenCenter Import wizard, you can import VMs from disk images (VHD and VMDK), Open Virtualization Format (OVF), and XenServer XVA format. You can even import VMs that have been created on other virtualization platforms, such as VMware or Microsoft.
Using the XenCenter Export wizard, you can export VMs to Open Virtualization Format files (OVF and OVA) and XenServer XVA files.
When importing and exporting VMs, a temporary VM named Transfer VM is used to perform the import/export of OVF/OVA packages and disk images.
The Transfer VM is a VM provided by XenServer that you use when you want to perform import or export operations of a virtual machine and in order to transfer the virtual machine's contents between the disk image file location and a XenServer Storage Repository (SR). Note that one Transfer VM runs for each import or export of a disk image.