Tweaking PXE boot times in Configuration Manager
- Scott Driver
- Nov 25, 2019
- 2 min read
In Configuration Manager we got a new option to tweak our PXE boot times, TFTPWindowsSize which we can change in the registry on our PXE enabled DP’s. PXE booting a machine can never be fast enough!
Location: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SMS\DP Name: RamDiskTFTPWindowSize Type: REG_DWORD
The default value is 1 (1 data block fills the window)We can also tweak the TFTPBlockSize which has been around for many versions of Configuration Manager.
Location: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SMS\DP
Name: RamDiskTFTPBlockSize Type: REG_DWORD Value: <customized block size>The default value is 4096 (4k).
So I did a lot of testing and when it comes down to it, you need to verify the settings that are best in your environment with your network configuration, your computermodels and so on. What we know for example:That HP Probook for instance doesn’t support a higher TFTPBlockSize value than 1456 otherwise it freezes. Vmware 5. x doesn’t support a higher value for TFTPWindowsSize than 8.I put together this list that could be a good starting point when testing out the different TFTP values, I used a Latitude E7450 and an Optiplex 7010.
Credit of report:
See the below PowerShell Script to help make the registry changes for you.
#SCCM TFTP boot changer 1.0
# Jorgen Nilsson CCMExec.com
$inputXML = @" <Window x:Name="SCCM_TFTP_Changer" x:Class="WpfApplication1.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local="clr-namespace:WpfApplication1" mc:Ignorable="d" Title="SCCM TFTP Changer" Height="267.52" Width="346.414"> <Grid Margin="0,0,2,-3"> <Grid.ColumnDefinitions> <ColumnDefinition Width="48*"/> <ColumnDefinition Width="7*"/> <ColumnDefinition Width="36*"/> <ColumnDefinition Width="246*"/> </Grid.ColumnDefinitions> <Button x:Name="Save" Content="Save" HorizontalAlignment="Left" Margin="42.8,139,0,0" VerticalAlignment="Top" Width="75" Grid.Column="3"/> <Label x:Name="label" Content="TFTP Blocksize value" HorizontalAlignment="Left" Margin="38,35,0,0" VerticalAlignment="Top" Width="177" Grid.ColumnSpan="4"/> <Button x:Name="Exit" Content="Exit" HorizontalAlignment="Left" Margin="137.8,139,0,0" VerticalAlignment="Top" Width="75" Grid.Column="3"/> <Button x:Name="Restart" Content="Restart WDS" HorizontalAlignment="Left" Margin="38,139,0,0" VerticalAlignment="Top" Width="75" Grid.ColumnSpan="4"/> <Label x:Name="label1" Content="TFTP WindowsSize value" HorizontalAlignment="Left" Margin="38,76,0,0" VerticalAlignment="Top" Width="142" Grid.ColumnSpan="4"/> <ComboBox x:Name="TFTPBlockSize" Grid.Column="3" HorizontalAlignment="Left" Margin="105.8,39,0,0" VerticalAlignment="Top" Width="120" SelectedIndex="0"> <ComboBoxItem Content="1024"/> <ComboBoxItem Content="1456"/> <ComboBoxItem Content="2048"/> <ComboBoxItem Content="4096"/> <ComboBoxItem Content="8192"/> <ComboBoxItem Content="16384"/> </ComboBox> <ComboBox x:Name="TFTPWindowsSize" Grid.Column="3" HorizontalAlignment="Left" Margin="105.8,76,0,0" VerticalAlignment="Top" Width="120" SelectedIndex="0"> <ComboBoxItem Content="1"/> <ComboBoxItem Content="2"/> <ComboBoxItem Content="4"/> <ComboBoxItem Content="8"/> <ComboBoxItem Content="16"/> </ComboBox> <TextBox x:Name="textBox" Grid.ColumnSpan="4" HorizontalAlignment="Left" Height="23" Margin="38,182,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="266" IsReadOnly="True"/> </Grid> </Window> "@ $inputXML = $inputXML -replace 'mc:Ignorable="d"','' -replace "x:N",'N' -replace '^<Win.*', '<Window' [void][System.Reflection.Assembly]::LoadWithPartialName('presentationframework') [xml]$XAML = $inputXML #Read XAML $reader=(New-Object System.Xml.XmlNodeReader $xaml) try{$Form=[Windows.Markup.XamlReader]::Load( $reader )} catch{Write-Host "Unable to load Windows.Markup.XamlReader. Double-check syntax and ensure .net is installed."} #=========================================================================== # Load XAML Objects In PowerShell #=========================================================================== $xaml.SelectNodes("//*[@Name]") | %{Set-Variable -Name "WPF$($_.Name)" -Value $Form.FindName($_.Name)} Function Get-FormVariables{ if ($global:ReadmeDisplay -ne $true){Write-host "If you need to reference this display again, run Get-FormVariables" -ForegroundColor Yellow;$global:ReadmeDisplay=$true} write-host "Found the following interactable elements from our form" -ForegroundColor Cyan get-variable WPF* } #$vmpicklistView.items.Add([pscustomobject]@{'VMName'=($_).Name;Status=$_.Status;Other="Yes"}) $WPFExit.Add_Click({$form.Close()}) $WPFRestart.Add_Click({ $WPFTextbox.Text=("Service is restarting") start-job -scriptblock {Restart-Service WDSServer} Start-Sleep -s 3 WaitUntilServices "WDSServer" "Running" $WPFTextbox.Text=("WDS Service Restarted")}) $WPFSave.Add_Click({ $WPFTextbox.Text=("Write to registry completed") Try { new-itemproperty "HKLM:\SOFTWARE\Microsoft\SMS\DP" -Name "RamDiskTFTPWindowSize" -Value $WPFTFTPWindowsSize.text -PropertyType Dword -Force -ErrorAction Stop new-itemproperty "HKLM:\SOFTWARE\Microsoft\SMS\DP" -Name "RamdiskTFTPBlockSize" -Value $WPFTFTPBlocksize.text -PropertyType Dword -Force -ErrorAction Stop } Catch { $WPFTextbox.Text=("Write to registry Failed! Check your permissions") } }) function WaitUntilServices($searchString, $status) { # Get all services where Name matches $searchString and loop through each of them. foreach($service in (Get-Service -Name $searchString)) { # Wait for the service to reach the $status or a maximum of 30 seconds $service.WaitForStatus($status, '00:01:00') } } #=========================================================================== # Shows the form #=========================================================================== # write-host "To show the form, run the following" -ForegroundColor Cyan $Form.ShowDialog() | out-null
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