As the virtual machine will most probably expect to see a hard disk built into its virtual computer, must be able to present real storage to the guest as a virtual hard disk. There are presently three methods by which to achieve this:

• can use large image files on a real hard disk and present them to a guest as a virtual hard disk. This is the most common method, described in .

• iSCSI storage servers can be attached to . This is described in .

• You can allow a virtual machine to access one of your host disks directly. This is an advanced feature, described in Using a Raw Host Hard Disk From a Guest.

Each such virtual storage device, such as an image file, iSCSI target, or physical hard disk, needs to be connected to the virtual hard disk controller that presents to a virtual machine. This is explained in the next section.