6.0.1

You can use Storage vMotion or cross-host Storage vMotion to transform virtual disks from one format to
another.
Thick Provision Lazy
Zeroed
Creates a virtual disk in a default thick format. Space required for the virtual
disk is allocated when the disk is created. 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. Virtual machines do not read
stale data from the physical device.
Thick Provision Eager
Zeroed
A type of thick virtual disk that supports clustering features such as Fault
Tolerance. Space required for the virtual disk is allocated at creation time. In
contrast to the thick provision lazy zeroed format, the data remaining on the
physical device is zeroed out when the virtual disk is created. It might take
longer to create virtual disks in this format than to create other types of
disks.
Thin Provision
Use this format to save storage space. For the thin disk, you provision as
much datastore space as the disk would require based on the value that you
enter for the virtual disk size. However, the thin disk starts small and at first,
uses only as much datastore space as the disk needs for its initial operations.
If the thin disk needs more space later, it can grow to its maximum capacity
and occupy the entire datastore space provisioned to it.
Thin provisioning is the fastest method to create a virtual disk because it
creates a disk with just the header information. It does not allocate or zero
out storage blocks. Storage blocks are allocated and zeroed out when they
are first accessed.
NOTE If a virtual disk supports clustering solutions such as Fault Tolerance,
do not make the disk thin.
You can manually inflate the thin disk, so that it occupies the entire
provisioned space. If physical storage space is exhausted and the thin
provisioned disk cannot grow, the virtual machine becomes unusable.
Large Capacity Virtual Disk Conditions and Limitations
Virtual machines with large capacity virtual hard disks, or disks greater than 2TB, must meet resource and
configuration requirements for optimal virtual machine performance.
The maximum value for large capacity hard disks is 62TB. When you add or configure virtual disks, always
leave a small amount of overhead. Some virtual machine tasks can quickly consume large amounts of disk
space, which can prevent successful completion of the task if the maximum disk space is assigned to the
disk. Such events might include taking snapshots or using linked clones. These operations cannot finish
when the maximum amount of disk space is allocated. Also, operations such as snapshot quiesce, cloning,
Storage vMotion, or vMotion in environments without shared storage, can take significantly longer to finish.
Virtual machines with large capacity disks have the following conditions and limitations:
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The guest operating system must support large capacity virtual hard disks.
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You can move or clone disks that are greater than 2TB to ESXi 5.5 or later hosts or to clusters that have
such hosts available.
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The datastore format must be VMFS5 or later or an NFS volume on a Network Attached Storage (NAS)
server.
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Virtual Flash Read Cache supports a maximum hard disk size of 16TBs.
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VMFS3 volumes are not supported. You cannot move disks greater than 2TB from a VMFS5 datastore
to a VMFS3 datastore.
vSphere Virtual Machine Administration
116 VMware, Inc.