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Drive Letter Assignment RRS feed

  • Question

  • We have a highly segmented and geographically diverse network which makes a centralized deployment server not feasible.  So, we deploy Litetouch images via USB flash drives.  We create a C drive for the OS, a D drive for the data drive and the E drive is generally the CD/DVD drive.  The deploy drive winds up being F or higher.  This has worked fine until Server 2012 R2/MDT 2013.  Now, during the deployment, the USB drive is taking the drive letter of D which causes apps to be installed onto it instead of the data drive.  I have tried talking people here into moving to a single C drive deployment which would greatly simplify the build and get around this problem but that is not a desired option.  I am not currently using custom WIMs but am not against it if it will solve this problem.  We are deploying onto Dell PE-RX20 series servers. 

    VMs, using the same build do not experience the problem.  The deploy drive comes up as F and everything installs as it should.  My thoughts there are that the image is mounted as an ISO and the OS cannot write to it so it treats it differently but the physical servers see it as a hard drive and install apps to it.

    Any assistance would be appreciated.

    Friday, February 21, 2014 8:48 PM

Answers

  • Generally, having applications and services that *assume* drive letters are persistent is considered bad. :^)

    Once the MDT deployment process has started, I wouldn't change the drive letters.

    *however* you might have some success by modifying the drive letters just *before* MDT restarts after the Install (Very Start of State Restore).

    You would want to modify the LTIBootStrap.vbs file to perform the drive letter swaps:

    (diskpart --> Select Vol D ; Assign M, Sel Vol E, Assign D, Sel Vol M, Assign E )


    Keith Garner - keithga.wordpress.com

    Thursday, February 27, 2014 12:21 AM
    Moderator

All replies

  • Format and Partition Disk

    This task sequence step configures and formats disk partitions on the target computer.Following is a brief listing of the settings that show how this step was originally configured in one of the MDTtask sequence templates.

    For more information about what script accomplishes this task and what properties are used, seeZTIDiskpart.wsf.

    The default configuration of the Format and Partition Disk task sequence step is:

    Properties

         
      

    Name

      
      

    Value

      

    Type

    Format and Partition Disk

    Name

    Format and Partition Disk

    Description

    Not specified

    Settings

         
      

    Name

      
      

    Value

      

    Disk number

    0

    Disk type

    Standard (MBR)

    Volume

    Within the Volume setting, the following   sub-settings are configured:

    • Partition Name.   OSDisk
    • Partition Type.   Primary
    • Use a percentage of remaining space. Selected
    • Size(%). 100
    • Use specific drive size.Not selected
    • Make this a boot partition. Selected
    • File System. NTFS
    • Quick Format.   Selected
    • Variable.Not   specified

    Options

         
      

    Name

      
      

    Value

      

    Disable this step

    Not selected

    Success codes

    0 3010


    Freelance-IT http://www.freelance-it.com.mx

    Saturday, February 22, 2014 12:25 AM
  • Formatting and partitioning the disk is not the problem.  As stated above, the drive letters are getting assigned differently on VMs and physical servers.
    Monday, February 24, 2014 3:35 PM
  • This has to do with device enumeration within WindowsPE. There's nothing you can do inside MDT itself change this behavior.

    Why do you install from USB? Do you actually physically go to a server to install it, why not mount an ISO using the iDRAC?

    For the recovery environment solution for MDT that I created, I use the following vbs script to change the drive letter based on the volume name.

    strComputer = "."
    Set objWMIService = GetObject("winmgmts:" _
        & "{impersonationLevel=impersonate}!\\" & strComputer & "\root\cimv2")
    Set colVolumes = objWMIService.ExecQuery _
        ("Select * from Win32_Volume Where Label = 'Recovery'")
    For Each objVolume in colVolumes
        objVolume.DriveLetter = "R:"
        objVolume.Put_
    Next	

    Perhaps you can use something similar in your case. Give all the drives a fixed name and then give it a different drive letter this way. You could make this part of your task sequence somewhere before the step where it'll format and partition the disks, or change the startup script of WindowsPE and have it execute before the litetouch wizard starts (look at the unattend.xml file inside the wim file or iso of windows PE). This way once the OS has been installed, the driver letters should appear in the correct order showing the partitions first of your disk drives, and then the first available drive letter for the usb drive (probably after the optical drive).


    Kind regards,

    Stephan Schwarz.


    If one of these posts answered your question or issue, please click on "Mark as answer".

    My Blog | Twitter: @Schwarz_Stephan | MCTS, MCITP, MCSA, MCSE (Charter Member), MCC-2011.
    Automatically determine target OU from ComputerName with PS for MDT2012 U1/ConfigMgr
    How to configure Windows RE/OEM Recovery Partition with MDT 2012 Update 1

    Monday, February 24, 2014 10:30 PM
  • Yes, physically going to the server with a USB flash drive is our current solution for physical servers.

    The iDRACs are currently isolated from direct access by Avocent UMG devices to provide a second level of security.  Also, streaming an ISO from the US to Asia does not work too well either due to the latency.

    The part that really bugs me is that this has worked fine up until MDT 2013/Server 2012 R2.  Before that, the drive enumeration was not a problem.  So, something has changed in the way that it takes place and it would be helpful to find out exactly what changed and if there is a way to get it to change back.

    I will try your script but I suspect that if I change the drive letter of the drive where MDT is running from, that will stop the task sequence.

    Monday, February 24, 2014 10:42 PM
  • Generally, having applications and services that *assume* drive letters are persistent is considered bad. :^)

    Once the MDT deployment process has started, I wouldn't change the drive letters.

    *however* you might have some success by modifying the drive letters just *before* MDT restarts after the Install (Very Start of State Restore).

    You would want to modify the LTIBootStrap.vbs file to perform the drive letter swaps:

    (diskpart --> Select Vol D ; Assign M, Sel Vol E, Assign D, Sel Vol M, Assign E )


    Keith Garner - keithga.wordpress.com

    Thursday, February 27, 2014 12:21 AM
    Moderator
  • Tuesday, October 7, 2014 8:39 AM
  • This doesn't work for me.

    Give me an error.

    • Edited by Maryary Tuesday, June 16, 2015 11:40 AM
    Tuesday, June 16, 2015 11:38 AM
  • Hi Keith,

    Can share or show on which line you add the diskpart?

    Monday, June 27, 2016 4:34 AM