6.5.1

Table Of Contents
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 on first
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.
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 the maximum extent size of 2 GB. You can use disks in this format
with hosted VMware products, such as VMware Fusion. However, you cannot power on the sparse
disk on an ESXi host unless you first re-import the disk with vmkfstools in a compatible format, such
as thick or thin.
Disk Formats on NFS Datastores
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 24 Storage Hardware Acceleration.
Creating a Virtual Disk
Use the vmkfstools command to create a virtual disk.
-c|--createvirtualdisk size[bB|sS|kK|mM|gG]
-d|--diskformat [thin|zeroedthick|eagerzeroedthick]
-W|--objecttype [file|vsan|vvol]
--policyFile fileName
vSphere Storage
VMware, Inc. 340