RemoveVirtualSystemSnapshot method of the Msvm_VirtualSystemManagementService class

Removes the specified snapshot from the virtual computer system. Any configuration or runtime state associated with the snapshot will be lost.

Syntax

uint32 RemoveVirtualSystemSnapshot(
  [in]  CIM_VirtualSystemSettingData REF SnapshotSettingData,
  [out] CIM_ConcreteJob              REF Job
);

Parameters

SnapshotSettingData [in]

Type: CIM_VirtualSystemSettingData

A reference to the CIM_VirtualSystemSettingData instance which represents the snapshot to be removed.

Job [out]

Type: CIM_ConcreteJob

An optional reference that is returned if the operation is executed asynchronously. If present, the returned reference to an instance of CIM_ConcreteJob can be used to monitor progress and to obtain the result of the method.

Return value

Type: uint32

If this method is executed synchronously, it returns 0 if it succeeds. If this method is executed asynchronously, it returns 4096 and the Job output parameter can be used to track the progress of the asynchronous operation. Any other return value indicates an error.

Completed with No Error (0)

Method Parameters Checked - Job Started (4096)

Failed (32768)

Access Denied (32769)

Not Supported (32770)

Status is unknown (32771)

Timeout (32772)

Invalid parameter (32773)

System is in use (32774)

Invalid state for this operation (32775)

Incorrect data type (32776)

System is not available (32777)

Out of memory (32778)

Remarks

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

Examples

The following C# sample removes a snapshot from a virtual system. The referenced utilities can be found in Common Utilities for the Virtualization Samples.

[!Important]
To function correctly, the following code must be run on the VM host server, and must be run with Administrator privileges.

using System;
using System.Management;

namespace HyperVSamples
{
    class RemoveVirtualSystemSnapshotClass
    {
        static ManagementObject GetLastVirtualSystemSnapshot(ManagementObject vm)
        {
            ManagementObjectCollection settings = vm.GetRelated(
                "Msvm_VirtualSystemsettingData",
                "Msvm_PreviousSettingData",
                null,
                null,
                "SettingData",
                "ManagedElement",
                false,
                null);

            ManagementObject virtualSystemsetting = null;
            foreach (ManagementObject setting in settings)
            {
                Console.WriteLine(setting.Path.Path);
                Console.WriteLine(setting["ElementName"]);
                virtualSystemsetting = setting;

            }

            return virtualSystemsetting;
        }

        static void RemoveVirtualSystemSnapshot(string vmName)
        {
            ManagementScope scope = new ManagementScope(@"root\virtualization", null);
            ManagementObject virtualSystemService = Utility.GetServiceObject(scope, "Msvm_VirtualSystemManagementService");

            ManagementBaseObject inParams = virtualSystemService.GetMethodParameters("RemoveVirtualSystemSnapshot");

            ManagementObject vm = Utility.GetTargetComputer(vmName, scope);

            ManagementObject vmSnapshot = GetLastVirtualSystemSnapshot(vm);

            inParams["SnapshotSettingData"] = vmSnapshot.Path.Path;

            ManagementBaseObject outParams = virtualSystemService.InvokeMethod("RemoveVirtualSystemSnapshot", inParams, null);

            if ((UInt32)outParams["ReturnValue"] == ReturnCode.Started)
            {
                if (Utility.JobCompleted(outParams, scope))
                {
                    Console.WriteLine("Snapshot was removed successfully.");

                }
                else
                {
                    Console.WriteLine("Failed to remove snapshot VM");
                }
            }
            else if ((UInt32)outParams["ReturnValue"] == ReturnCode.Completed)
            {
                Console.WriteLine(outParams["SnapshotsettingData"].ToString());
                Console.WriteLine("Snapshot was removed successfully.");
            }
            else
            {
                Console.WriteLine("Remove virtual system snapshot failed with error {0}", outParams["ReturnValue"]);
            }

            inParams.Dispose();
            outParams.Dispose();
            vmSnapshot.Dispose();
            vm.Dispose();
            virtualSystemService.Dispose();
        }

        static void Main(string[] args)
        {
            if (args != null && args.Length != 1)
            {
                Console.WriteLine("Usage: RemoveVirtualSystemSnapshot vmName");
                return;
            }
            RemoveVirtualSystemSnapshot(args[0]);
        }
    }
}

The following VBScript sample removes a snapshot from a virtual system.

[!Important]
To function correctly, the following code must be run on the VM host server, and must be run with Administrator privileges.

option explicit 

dim objWMIService
dim managementService
dim fileSystem

const JobStarting = 3
const JobRunning = 4
const JobCompleted = 7
const wmiStarted = 4096
const wmiSuccessful = 0


Main()

'-----------------------------------------------------------------
' Main
'-----------------------------------------------------------------
Sub Main()
    dim computer, objArgs, vmName, vm, snapshotSetting
    
    set fileSystem = Wscript.CreateObject("Scripting.FileSystemObject")
    computer = "."
    set objWMIService = GetObject("winmgmts:\\" & computer & "\root\virtualization")
    set managementService = objWMIService.ExecQuery("select * from Msvm_VirtualSystemManagementService").ItemIndex(0)
    
    set objArgs = WScript.Arguments
    if WScript.Arguments.Count = 1 then
        vmName = objArgs.Unnamed.Item(0)
    else
        WScript.Echo "usage: cscript RemoveVirtualSystemSnapshot.vbs vmName"
        WScript.Quit(1)
    end if
 
    set vm = GetComputerSystem(vmName)
    set snapshotSetting = GetComputerSystemSnapshotSettings(vm)

    if RemoveVirtualSystemSnapshot(snapshotSetting) then
        WriteLog "Done"
        WScript.Quit(0)
    else
        WriteLog "RemoveVirtualSystemSnapshot Failed."
        WScript.Quit(1)
    end if
End Sub

'-----------------------------------------------------------------
' Retrieve Msvm_VirtualComputerSystem from base on its ElementName
'-----------------------------------------------------------------
Function GetComputerSystem(vmElementName)
    On Error Resume Next
    dim query
    query = Format1("select * from Msvm_ComputerSystem where ElementName = '{0}'", vmElementName)
    set GetComputerSystem = objWMIService.ExecQuery(query).ItemIndex(0)
    if (Err.Number <> 0) then
        WriteLog Format1("Err.Number: {0}", Err.Number)
        WriteLog Format1("Err.Description:{0}",Err.Description)
        WScript.Quit(1)
    end if
End Function

'-----------------------------------------------------------------
' Retrieve the latest Msvm_VirtualComputerSystem snapshot
'-----------------------------------------------------------------
Function GetComputerSystemSnapshotSettings(computerSystem)
    On Error Resume Next
    dim query
    query = Format1("ASSOCIATORS OF {{0}} WHERE resultClass = Msvm_VirtualSystemsettingData AssocClass = Msvm_PreviousSettingData", computerSystem.Path_.Path)
    set GetComputerSystemSnapshotSettings = objWMIService.ExecQuery(query).ItemIndex(0)
    if (Err.Number <> 0) then
        WriteLog Format1("Err.Number: {0}", Err.Number)
        WriteLog Format1("Err.Description:{0}",Err.Description)
        WScript.Quit(1)
    end if
End Function

'-----------------------------------------------------------------
' Remove a virtual system Snapshot
'-----------------------------------------------------------------
Function RemoveVirtualSystemSnapshot(snapshotSettingData)

    dim objInParam, objOutParams
    
    RemoveVirtualSystemSnapshot = false
    set objInParam = managementService.Methods_("RemoveVirtualSystemSnapshot").InParameters.SpawnInstance_()
    objInParam.SnapshotSettingData = snapshotSettingData.Path_.Path
    
    set objOutParams = managementService.ExecMethod_("RemoveVirtualSystemSnapshot", objInParam)

    if objOutParams.ReturnValue = wmiStarted then
        if (WMIJobCompleted(objOutParams)) then
            RemoveVirtualSystemSnapshot = true
        end if
    elseif objOutParams.ReturnValue = wmiSuccessful then
        RemoveVirtualSystemSnapshot = true
    else
        WriteLog Format1("RemoveVirtualSystemSnapshot failed with ReturnValue {0}", objOutParams.ReturnValue)
    end if

End Function

'-----------------------------------------------------------------
' Handle wmi Job object
'-----------------------------------------------------------------
Function WMIJobCompleted(outParam)

    dim WMIJob, jobState
    WMIJobCompleted = true

    set WMIJob = objWMIService.Get(outParam.Job)
    
    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 (WMIJob.JobState <> JobCompleted) then
        WriteLog Format1("ErrorDescription:{0}", WMIJob.ErrorDescription)
        WriteLog Format1("ErrorCode:{0}", WMIJob.ErrorCode)
        WMIJobCompleted = false
    end if

End Function

'-----------------------------------------------------------------
' Create the console log files.
'-----------------------------------------------------------------
Sub WriteLog(line)
    dim fileStream
    set fileStream = fileSystem.OpenTextFile(".\RemoveVirtualSystemSnapshot.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

Msvm_VirtualSystemManagementService

DestroySnapshot (V2)