Data Object - VirtualDiskFlatVer2BackingInfo(vim.vm.device.VirtualDisk.FlatVer2BackingInfo)

A content ID indicates the logical contents of the disk backing and its parents.

This property is only guaranteed to be up to date if this disk backing is not currently being written to by any virtual machine.

The only supported operation is comparing if two content IDs are equal or not. The guarantee provided by the content ID is that if two disk backings have the same content ID and are not currently being written to, then reads issued from the guest operating system to those disk backings will return the same data.

This field is valid only for a delta disk.

See DeltaDiskFormat for the supported formats. If not specified, the default value used is redoLogFormat.

If nativeFormat is specified and the datastore does not support this format or the parent is on a different datastore, DeltaDiskFormatNotSupported is thrown.

vSphere server does not support relocation of virtual machines with nativeFormat. An exception is thrown for such requests.

This field is valid only for a delta disk and may specify more detailed information for the delta disk format specified in deltaDiskFormat.

If redoLogFormat is specified for the deltaDiskFormat, see DeltaDiskFormatVariant for the supported formats. If this is not specified for redoLogFormat, the default value used is vmfsSparseVariant.

For other delta disk formats, this currently remains unspecified.

• vim.vm.device.VirtualDiskOption.DiskMode#persistent
• vim.vm.device.VirtualDiskOption.DiskMode#independent_persistent
• vim.vm.device.VirtualDiskOption.DiskMode#independent_nonpersistent
• vim.vm.device.VirtualDiskOption.DiskMode#nonpersistent
• vim.vm.device.VirtualDiskOption.DiskMode#undoable
• vim.vm.device.VirtualDiskOption.DiskMode#append

Virtual disks on some filesystems like VMFS3 are zeroed-out lazily so that disk creation time doesn't take too long. However, clustering applications and features like Fault Tolerance require that the virtual disk be completely scrubbed. This setting allows controlling the scrubbing policy on a per-disk basis.

If this flag is unset or set to false when creating a new disk, the disk scrubbing policy will be decided by the filesystem. If this flag is unset or set to false when editing an existing disk, it is ignored. When returned as part of a VirtualMachineConfigInfo, this property may be unset if its value is unknown.

A delta disk backing is a way to preserve a virtual disk backing at some point in time. A delta disk backing is a file backing which in turn points to the original virtual disk backing (the parent). After a delta disk backing is added, all writes go to the delta disk backing. All reads first try the delta disk backing and then try the parent backing if needed.

A delta disk backing can be added to a disk either implicitly during snapshot operations, or explicitly during create or reconfigure of the virtual machine.

Note that the type of the backing is consistent throughout the chain; any new delta disk backing which is added is of the same type as the original disk . Also note that since the parent backing is not being written to, it is possible that the parent backing may be shared among multiple disks belonging to multiple virtual machines.

During virtual machine CreateVM_Task and ReconfigVM_Task this property is only checked if the VirtualDeviceConfigSpec specifies an add operation with a create file operation. In this case, a new delta disk backing is created which points to the parent disk backing. Only the fileName property is important; all other properties will be ignored. The parent backing is assumed to exist and will not be recursively created.

This property may only be set if deltaDiskBackingsSupported is true.

Flag to indicate to the underlying filesystem, whether the virtual disk backing file should be allocated lazily (using thin provisioning). This flag is only used for file systems that support configuring the provisioning policy on a per file basis, such as VMFS3.

When specified as part of a VirtualMachineConfigSpec, this property applies only when creating a new virtual disk; it is ignored when editing an existing virtual disk.

see perFileThinProvisioningSupported