CreateDynamicVirtualHardDisk method of the Msvm_ImageManagementService class

Creates a dynamically expanding virtual hard disk (.vhd) file.

Syntax

uint32 CreateDynamicVirtualHardDisk(
  [in]  string              Path,
  [in]  uint64              MaxInternalSize,
  [out] CIM_ConcreteJob REF Job
);

Parameters

Path [in]

Type: string

A fully qualified path that specifies the location of the new file.

MaxInternalSize [in]

Type: uint64

The maximum size of the virtual hard disk, in bytes. The specified size must be a multiple of 512 or this method will fail. If this value is 0, the default size of 3 MB is chosen.

Job [out]

Type: CIM_ConcreteJob

A reference to the job (can be null if the task is completed).

Return value

Type: uint32

This method can return one of the following values.

Remarks

Access to the Msvm_ImageManagementService class might be restricted by UAC Filtering. For more information, see User Account Control and WMI.

Examples

The following C# example creates a dynamically expanding virtual hard disk file. The referenced utilities can be found in Common Utilities for the Virtualization Samples.

using System;
using System.Management;

namespace HyperVSamples
{
    class CreateDynamicVHD
    {
        const UInt64 Size1G = 0x40000000;
        static void CreateDynamicVirtualHardDisk(string path, UInt64 maxInternalSize)
        {

            ManagementScope scope = new ManagementScope(@"root\virtualization", null);
            ManagementObject imageService = Utility.GetServiceObject(scope, "Msvm_ImageManagementService");

            ManagementBaseObject inParams = imageService.GetMethodParameters("CreateDynamicVirtualHardDisk");
            inParams["Path"] = path;
            inParams["MaxInternalSize"] = maxInternalSize * Size1G;
            ManagementBaseObject outParams = imageService.InvokeMethod("CreateDynamicVirtualHardDisk", inParams, null);
            if ((UInt32)outParams["ReturnValue"] == ReturnCode.Started)
            {
                if (Utility.JobCompleted(outParams, scope))
                {
                    Console.WriteLine("{0} was created successfully.", inParams["Path"]);
                }
                else
                {
                    Console.WriteLine("Unable to create {0}", inParams["Path"]);
                }
            }

            inParams.Dispose();
            outParams.Dispose();
            imageService.Dispose();

        }

        static void Main(string[] args)
        {
            if (args != null && args.Length != 2)
            {
                Console.WriteLine("Usage: CreateDynamicVHD path, maxInternalSize");
                Console.WriteLine("maxInternalSize: unit in 1 gigabyte");
                return;
            }
            string path = args[0];
            UInt64 maxInternalSize = UInt64.Parse(args[1]);
            CreateDynamicVirtualHardDisk(path, maxInternalSize);
        }
    }
}

The following VBScript example creates a dynamically expanding virtual hard disk file.

option explicit

dim objWMIService
dim managementService
dim fileSystem

const Size1G = &H40000000

const JobStarting = 3
const JobRunning = 4
const JobCompleted = 7
const wmiStarted = 4096

Main()

'-----------------------------------------------------------------
' Main
'-----------------------------------------------------------------
Sub Main()
    
    dim computer, objArgs, vhdPath, dynmicVHD, size

    set fileSystem = Wscript.CreateObject("Scripting.FileSystemObject")

    computer = "."
    set objWMIService = GetObject("winmgmts:\\" & computer & "\root\virtualization")
    set managementService = objWMIService.ExecQuery("Select * from Msvm_ImageManagementService").ItemIndex(0)

    set objArgs = WScript.Arguments
    if WScript.Arguments.Count = 2 then
       vhdPath = objArgs.Unnamed.Item(0)
       size = objArgs.Unnamed.Item(1)
    else
       WScript.Echo "usage: cscript CreateDyanmicVHD.vbs VHDFilePath, size"
       WScript.Echo "size: unit in Gigabyte"
       WScript.Quit(1)
    end if

    if CreateDynamicVirtualHardDisk(vhdPath, size) then
        WriteLog "Done"
        WScript.Quit(0)
    else
        WriteLog "CreateVHD failed"
        WScript.Quit(1)
    end if


End Sub

'-----------------------------------------------------------------
' Execute CreateDynamicVirtualHardDisk method
'-----------------------------------------------------------------
Function CreateDynamicVirtualHardDisk(vhdPath, size)
    WriteLog Format2("Sub CreateFixedVirtualHardDisk({0}, {1})",  vhdPath, size)
    
    dim objInParam, objOutParams
    
    CreateDynamicVirtualHardDisk = false

    set objInParam = managementService.Methods_("CreateDynamicVirtualHardDisk").InParameters.SpawnInstance_()
    objInParam.Path = vhdPath
    objInParam.MaxInternalSize = size * Size1G

    set objOutParams = managementService.ExecMethod_("CreateDynamicVirtualHardDisk", objInParam)

    if (WMIMethodStarted(objOutParams)) then
        if (WMIJobCompleted(objOutParams)) then
            WriteLog Format1("'{0}' was created successfully!", vhdPath)
            CreateDynamicVirtualHardDisk = true
        end if
    end if

End Function


'-----------------------------------------------------------------
' Handle wmi return values
'-----------------------------------------------------------------
Function WMIMethodStarted(outParam)
    WriteLog "Function WMIMethodStarted"
    
    dim wmiStatus
    
    WMIMethodStarted = false

    if Not IsNull(outParam) then
        wmiStatus = outParam.ReturnValue

        if  wmiStatus = wmiStarted then
            WMIMethodStarted = true
        else
            WriteLog Format2("Failed to create VHD ConcreteJob with Error {1}.", wmiStatus)
        end if
   end if

End Function



'-----------------------------------------------------------------
' Handle wmi Job object
'-----------------------------------------------------------------
Function WMIJobCompleted(outParam)
    WriteLog "Function WMIJobCompleted"
    
    dim WMIJob, jobState

    set WMIJob = objWMIService.Get(outParam.Job)

    WMIJobCompleted = true

    jobState = WMIJob.JobState

    while jobState = JobRunning or jobState = JobStarting
        WriteLog Format1("In progress... {0}% completed.",WMIJob.PercentComplete)
        WScript.Sleep(1000)
        set WMIJob = objWMIService.Get(outParam.Job)
        jobState = WMIJob.JobState
    wend

    if (jobState <> JobCompleted) then
        WriteLog Format1("ErrorCode:{0}", WMIJob.ErrorCode)
        WriteLog Format1("ErrorDescription:{0}", WMIJob.ErrorDescription)
        WMIJobCompleted = false
    end if

End Function

'-----------------------------------------------------------------
' Create the console log files.
'-----------------------------------------------------------------
Sub WriteLog(line)
    dim fileStream
    set fileStream = fileSystem.OpenTextFile(".\CreateDynamicVHD.log", 8, true)
    WScript.Echo line
    fileStream.WriteLine line
    fileStream.Close

End Sub


'------------------------------------------------------------------------------
' The string formatting functions to avoid string concatenation.
'------------------------------------------------------------------------------
Function Format2(myString, arg0, arg1)
    Format2 = Format1(myString, arg0)
    Format2 = Replace(Format2, "{1}", arg1)
End Function

'------------------------------------------------------------------------------
' The string formatting functions to avoid string concatenation.
'------------------------------------------------------------------------------
Function Format1(myString, arg0)
    Format1 = Replace(myString, "{0}", arg0)
End Function

Requirements

See also

CreateVirtualHardDisk (V2)

CIM_ConcreteJob

Msvm_ImageManagementService