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IVssDifferentialSoftwareSnapshotMgmt::AddDiffArea method (vsmgmt.h)

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The AddDiffArea method adds a shadow copy storage area association for the specified volume. If the association is not supported, an error code will be returned.

Syntax

HRESULT AddDiffArea(
  [in] VSS_PWSZ pwszVolumeName,
  [in] VSS_PWSZ pwszDiffAreaVolumeName,
  [in] LONGLONG llMaximumDiffSpace
);

Parameters

[in] pwszVolumeName

The name of the volume that will be the source of shadow copies. This volume is associated with a shadow copy storage area on the pwszDiffAreaVolumeName volume.

The name of the volume must be in one of the following formats and must include a trailing backslash (\):

  • The path of a mounted folder, for example, Y:\MountX\
  • A drive letter, for example, D:\
  • A volume GUID path of the form \\?\Volume{GUID}\ (where GUID identifies the volume)

[in] pwszDiffAreaVolumeName

The name of the volume that will contain the shadow copy storage area to be associated with the pwszVolumeName volume.

The name of the volume must be in one of the following formats and must include a trailing backslash (\):

  • The path of a mounted folder
  • A drive letter, for example, D:\
  • A volume GUID path of the form \\?\Volume{GUID}\ (where GUID identifies the volume)

[in] llMaximumDiffSpace

The maximum size, in bytes, of the shadow copy storage area on the volume. This value must be at least 320 MB, up to the system-wide limit. If this value is –1, the maximum size is unlimited.

Windows Server 2003:  Prior to Windows Server 2003 with SP1, the shadow copy storage area size was fixed at 100 MB.

Return value

This method can return one of these values.

Value Meaning
S_OK
 Successfully added the shadow copy storage area association.
E_ACCESSDENIED
 Caller does not have sufficient backup privileges or is not an administrator.
E_INVALIDARG
 One of the parameter values is not valid.
E_OUTOFMEMORY
 The caller is out of memory or other system resources.
VSS_E_MAXIMUM_DIFFAREA_ASSOCIATIONS_REACHED
 The maximum number of shadow copy storage areas has been added to the shadow copy source volume. The specified shadow copy storage volume was not associated with the specified shadow copy source volume.
VSS_E_NESTED_VOLUME_LIMIT
 The specified volume is nested too deeply to participate in the VSS operation.

Windows Server 2008, Windows Vista, Windows Server 2003 and Windows XP:  This return code is not supported.
VSS_E_OBJECT_ALREADY_EXISTS
 The association between the pwszVolumeName and pwszDiffAreaVolumeName volumes already exists.
VSS_E_PROVIDER_VETO
 Expected provider error. The provider logged the error in the event log. For more information, see Event and Error Handling Under VSS.
VSS_E_UNEXPECTED
 Unexpected error. The error code is logged in the error log file. For more information, see Event and Error Handling Under VSS.

Windows Server 2008, Windows Vista, Windows Server 2003 and Windows XP:  This value is not supported until Windows Server 2008 R2 and Windows 7. E_UNEXPECTED is used instead.
VSS_E_VOLUME_NOT_SUPPORTED
 The pwszDiffAreaVolumeName volume is not an NTFS volume or has insufficient free space.

Remarks

A shadow copy storage area association cannot be created if any shadow copies already exist for the pwszVolumeName volume or if there is already a shadow copy storage area association for that volume.

The shadow copy storage area for a virtual hard disk (VHD) source volume must reside on the same volume. Likewise, a shadow copy storage area can only be created on a VHD volume if the source volume is the same for both volumes.

Windows Server 2008, Windows Vista, Windows Server 2003 and Windows XP:  VHDs are not supported.

To change the size of a shadow copy storage area, use the IVssDifferentialSoftwareSnapshotMgmt::ChangeDiffAreaMaximumSize or IVssDifferentialSoftwareSnapshotMgmt2::ChangeDiffAreaMaximumSizeEx method. You can delete a shadow copy storage area by changing its size to zero.

Requirements

Requirement Value
Minimum supported client None supported
Minimum supported server Windows Server 2003 [desktop apps only]
Target Platform Windows
Header vsmgmt.h

See also

IVssDifferentialSoftwareSnapshotMgmt