6.0.1

Virtual Disk Options
Virtual disk options allow you to set up, migrate, and manage virtual disks stored in VMFS and NFS le
systems. You can also perform most of these tasks through the vSphere Web Client.
Supported Disk Formats
When you create or clone a virtual disk, you can use the -d --diskformat suboption to specify the format for
the disk.
Choose from the following formats:
n
zeroedthick (default) – Space required for the virtual disk is allocated during creation. Any data
remaining on the physical device is not erased during creation, but is zeroed out on demand at a later
time on rst write from the virtual machine. The virtual machine does not read stale data from disk.
n
eagerzeroedthick – Space required for the virtual disk is allocated at creation time. In contrast to
zeroedthick 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.
n
thin – Thin-provisioned virtual disk. Unlike with the thick format, space required for the virtual disk is
not allocated during creation, but is supplied, zeroed out, on demand at a later time.
n
rdm:device – Virtual compatibility mode raw disk mapping.
n
rdmp:device – Physical compatibility mode (pass-through) raw disk mapping.
n
2gbsparse – A sparse disk with 2GB maximum extent size. You can use disks in this format with hosted
VMware products, such as VMware Fusion, Player, Server, or Workstation. However, you cannot power
on sparse disk on an ESXi host unless you rst re-import the disk with vmkfstools in a compatible
format, such as thick or thin.
See “Migrate Virtual Machines Between Dierent VMware Products,” on page 290.
NFS Disk Formats
The only disk formats you can use for NFS are thin, thick, zeroedthick and 2gbsparse.
Thick, zeroedthick and thin formats usually behave the same because the NFS server and not the ESXi host
determines the allocation policy. The default allocation policy on most NFS servers is thin. However, on
NFS servers that support Storage APIs - Array Integration, you can create virtual disks in zeroedthick
format. The reserve space operation enables NFS servers to allocate and guarantee space.
For more information on array integration APIs, see Chapter 23, “Storage Hardware Acceleration,” on
page 259.
Creating a Virtual Disk
Use the vmkfstools command to create a virtual disk.
-c --createvirtualdisk size[kK|mM|gG]
-a --adaptertype [buslogic|lsilogic|ide|lsisas|pvscsi] srcfile
-d --diskformat [thin|zeroedthick|eagerzeroedthick]
-W --objecttype [file|vsan|vvol]
--policyFile fileName
This option creates a virtual disk at the specied path on a datastore. Specify the size of the virtual disk.
When you enter the value for size, you can indicate the unit type by adding a sux of k (kilobytes), m
(megabytes), or g (gigabytes). The unit type is not case sensitive. vmkfstools interprets either k or K to mean
kilobytes. If you don’t specify a unit type, vmkfstools defaults to bytes.
Chapter 26 Using vmkfstools
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