When you place a physical disk under VxVM control, a VM disk is assigned to the physical disk. A VM disk is under VxVM control and is usually in a disk group. Each VM disk corresponds to at least one physical disk or disk partition. VxVM allocates storage from a contiguous area of VxVM disk space.

A VM disk typically includes a public region (allocated storage) and a small private region where VxVM internal configuration information is stored.

Each VM disk has a unique disk media name (a virtual disk name). You can either define a disk name of up to 31 characters, or allow VxVM to assign a default name that takes the form diskgroup##, where diskgroup is the name of the disk group to which the disk belongs.

Figure: VM disk example shows a VM disk with a media name of disk01 that is assigned to the physical disk, devname.