Thick Provision Lazy Zeroed (default) – Space required for the virtual disk is allocated during the creation of the disk file. Any data remaining on the physical device is not erased during creation, but is zeroed out on demand at a later time on first write from the virtual machine. The virtual machine does not read stale data from disk.

Thick Provision Eager Zeroed – Space required for the virtual disk is allocated at creation time. In contrast to thick provision format, the data remaining on the physical device is zeroed out during creation. It might take much longer to create disks in this format than to create other types of disks.

Thin Provision – Space required for the virtual disk is not allocated during creation, but is supplied and zeroed out, on demand at a later time.

thick – Space required for the virtual disk is allocated during creation. This type of formatting does not zero out any old data that might be present on this allocated space. A non-root user cannot create disks of this format.

rdm – Virtual compatibility mode for raw disk mapping.

rdmp – Physical compatibility mode (pass-through) for raw disk mapping.

raw – Raw device.

2gbsparse – A sparse disk with 2GB maximum extent size. You can use disks in this format with other VMware products, however, you cannot power on sparse disk on a ESX host till you reimport the disk with vmkfstools in a compatible format, such as thick or thin.

monosparse – A monolithic sparse disk. You can use disks in this format with other VMware products.

Note: monosparse disks are not supported in ESXi 5.5 and later.

monoflat – A monolithic flat disk. You can use disks in this format with other VMware products.