This partition is called a LUN. For example, most PC users will be familiar with the partition of a single disk into a C: drive for applications and data, plus a D: drive for recovery purposes.

These datastores are contained on logical unit numbers, which are logical volumes that can be used as storage space on a disk. You can add and associate a LUN with an ESX host in VMware ...

There is no separate LUN format for Hyper-V. VHD files allocated as thin volumes (known as dynamic hard disks) expand by increasing the size of the file and consuming more space on disk.