VirtualBox

I am presenting at Exchange Connections 2010 later this year, and I need to set up some demo machines. I need my demo to run Exchange 2010, which is a 64bit application and I do not have guaranteed internet access so I cannot run my demo’s via my lab machines in the UK.

But I cannot use Virtual PC 7 installed on my Windows 7 laptop. And I do not want to reinstall my laptop with Windows 2008 Server to allow me to run Hyper-V.

So I have installed Oracles VM desktop product, VirtualBox. And this blog is just to describe how to do what we know as base images and differencing files in Virtual PC/Hyper-V on VirtualBox, and to use the VHD disk format which VirtualBox supports so that I have the option of moving my virtual servers between Virtual PC (if it ever supports x64 guests), Hyper-V servers and VirtualBox.

So to create a new VHD hard disk for use in VirtualBox open a command prompt, change to the directory in which you installed VirtualBox (probably C:\Program Files\Oracle\VirtualBox) and run the following command:

VBoxManage createhd --filename "path\filename.vhd" --size 130048 --format VHD --variant standard --remember

This will create a dynamically expanding hard disk in the location specified, in the Microsoft VHD format, and 130048KB (127GB).

Next you create a new virtual guest in the VirtualBox application (or via the VBoxManage command line if you wish) that uses this existing disk.

Boot this virtual guest, and then install the required OS and patches etc. Once this guest is ready to be a base image you can shut it down. If you are going to use this base images as a Domain Controller then you need to reset the SID’s on the device using either NewSID from Sysinternals or Sysprep before you move onto the next step.

Now that you have the base image, you need to mark it as such in VirtualBox. This is done from the command line:

VBoxManage modifyhd "path\filename.vhd" --type immutable

And then you need to delete the virtual guest settings that you used to create this disk. This disk is not deleted.

To create the virtual guests that use the “immutable” disk (aka parent/base disk) in Virtual PC/Hyper-V you would need to make a second disk, but not in VirtualBox. Here you just use the same disk. As you have marked it as immutable a snapshot disk will be created (in the .VirtualBox folder of your profile) and all changes will be written to this disk instead.

Restrictive Throttling Policies in Exchange 2010

Exchange Server 2010 has the ability to limit user and administrative actions. But in testing this feature in a lab I set the default policy (which by default affects everyone, including the Administrator account) to a policy that stopped me undoing the policy again!

I ran Set-ThrottlingPolicy def* -PowerShellMaxConcurrency 1 -PowerShellMaxCmdletsTimePeriod 1000 -PowerShellMaxCmdlets 1 which had the effect of saying I could open one PowerShell session (that is okay - its my lab environment), run a single cmdlet (maybe a bit too low) and to run one cmdlet every 1000 seconds. I had not worked out that 1000 seconds is over 15 minutes.

The problem came two days later, starting Exchange Management Shell and connecting to the remote PowerShell endpoint obviously invokes more than one cmdlet. The second cmdlet is terminated, and so Exchange Management Shell cannot start - ever!

The error message I got was:

The WS-Management service cannot process the request. The user load quota of X requests per Y seconds has been exceeded. Send future requests at a slower rate or raise the quota for this user. The next request from this user will not be approved for at least Z milliseconds.

X is the value of PowerShellMaxCmdlets and Y is the PowerShellMaxCmdletsTimePeriod

So to fix I cracked open ADSIEdit - not to be done lightly, as it runs the risk of destroying the entire Exchange organization and Active Directory.

To fix this and reset the Throttling Policy connect to the Configuration Naming Context in ADSIEdit and navigate to CN=Global Settings,CN=organization name,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=domain. Open CN=Default Throttling Policy_guid and edit msExchPowerShellThrottlingPolicyState to read:

v~0~con~18~cmds~-1~per~-1~que~-1~excmds~-1

Once Active Directory replicates you will be able to run PowerShell cmdlets in Exchange Management Shell. The first cmdlet I would run would be one to ensure that you are back to the default policy just in case you made a mistake in ADSIEdit:

Set-ThrottlingPolicy def* -PowerShellMaxConcurrency 18 -PowerShellMaxCmdletsTimePeriod $null -PowerShellMaxCmdlets $null -PowerShellCmdletQueueDepth $null

RegRead and Error -2147024894

Error -2147024894 appears when you use the WScript.Shell RegRead object to read a registry key that does not exist. But why would you get this error when the key does exist!

Probably because you are running your code inside a HTA and using a 64bit operating system.

The HTA environment is mshta, which is 32 bit. This means that when your code reads registry entries such as HKLM\Software\Microsoft\Windows via a HTA on a 64bit OS it is really reading HKLM\Software\Wow6432Node\Microsoft\Windows. Therefore if you have values or keys at HKLM\Software\Microsoft\Windows and not at HKLM\Software\Wow6432Node\Microsoft\Windows then you will get error -2147024894 because the value/key cannot be found.

Run the HTA on a 32bit OS and it work fine. But most confusing is that if you take the code from the HTA script and save it to a .vbs or .js file and run it (on the 64bit OS) via wscript or cscript then the script will find the registry key at HKLM\Software\Microsoft\Windows because in this instance the wscript or cscript environment is 64bit.

Of course this is true for any HKLM\Software registry entry.

Scheduling Backup on Microsoft Hyper-V Server

To do a backup of the virtual machines installed on your Hyper-V Server (2008 or 2008 R2 editions) you need to complete the following steps.

1. Install the backup feature by typing start /w ocsetup WindowsServerBackup from the command prompt.
2. Get a list of the drives on which Hyper-V Server has stored virtual machines. This will be C: unless you have made changes.
3. Determine the times you want to run the backup at.
4. Determine the drive letter of the removable disk by typing at the command prompt each of the following commands
   1. diskpart
   2. list volume
   3. The disk drive letter will be displayed for the disk that matches the size of your removable disk.
   4. Type exit to exit diskpart.
5. From the command prompt type wbadmin enable backup -addtarget:x: -schedule:hh:mm,h2:m2 -include:y:,z: -systemState -allCritical to backup to drive X: the contents of drives Y: and Z:, the system state and all drives critical to the running of the server.
6. Confirm you want to schedule the backup at times HH:MM and H2:M2 (for twice a day). If you want one backup a day use HH:MM and if you want more than two just comma separate a group of times. Enter times as per local timezone. Check the current time on the Hyper-V Server by typing time from the command prompt.
7. Start a backup now if you want by typing wbadmin start backup and confirming to use the same settings as the scheduled backup.
8. Backup will proceed in the console. If you log out backup will remain running.
9. Enter wbadmin enable backup to see the settings you have enabled.
10. Type wbadmin get versions to see what backups have completed.

Booting a Server with a USB Key

There are numerous instructions on the internet for creating and booting a server with a USB key, but they were all complex or hard to read – even for a techy like myself.

So I thought I would rewrite a simple list of instructions to allow you to create a DOS bootable USB pendrive/key that you can use for any purpose (i.e. flashing BIOS's and other low level functions, as well as booting into other operating systems).

1. Download download bootable_usb.zip from www.lowfps.com. This is the website these instructions are based on, but I wanted something clearer than that.
2. Extract the download to a temporary location (i.e. C:\Users)
3. Run the HP bootable media.exe program and install the software.
4. Insert the USB key you want to use – it will get wiped during this process to backup its contents if needed.
5. Run the HP USB Disk Storage Format Tool from the desktop or Start Menu. If you are using Vista or later then you will need to run the program in elevated mode (right-click program and choose Run as administrator).
6. Select your USB key and choose to do format the key with the FAT or FAT32 file system. Choose Quick Format and select Create DOS Startup Disk. Pick the sub-option "Using DOS files located at" and select the same "DOS Files" subfolder in the location where you extracted the download too (C:\Users in my above example).
7. Click OK. The USB key will be wiped during this process and a copy of the core files for Microsoft Millennium DOS will copied to the key.
8. When complete copy to the key any files that you need to execute in DOS mode on the PC (for example I needed to update the BIOS on a x64 Windows Server 2008 Server Core installation running on a Dell Optiplex 755 and it said this was not allowed). The files you copy to the key must work in DOS though.
9. Shutdown the server and insert the USB key. You must do a hard reboot, a restart will not work.
10. Restart the server and press F12 to bring up the one-time boot menu (if you do not have this option then go into setup [Del or F2] and ensure USB booting is enabled and set to the primary option).
11. In the boot menu choose the USB key option.
12. From the C:\ prompt run the programs you need to start. Note that this is old style DOS and not the Command Prompt in later versions of Windows – so no command completion using the TAB key. So place the files in or near the root folder.

Windows Backup Failure on Windows Server 2008

I recently had a case where Windows Backup would fail at approx. 75% complete during a full backup. The backup utility and command line both reported that "The system cannot find the file specified". The Event Viewer/Application... Services/ Microsoft/ Windows/ Backup/ Operational reads "Backup target is running low on free space. Future backups to this target may fail for want of enough space." and then at the same time and immediately after that we get "Backup started at TimeZ' failed with following error code '2147942402'" which means file not found or unknown error.

After a series of email communications with the Windows Backup team at Microsoft India (where, incidentally, the program was developed) the answer came back that I should run chkdsk /r and reboot the server. As this process can take hours this occurred out of hours and actually in my case needed to be repeated twice. A normal chkdsk command, run whilst the server was online, reported that the disk had errors and could not continue.

After running chkdsk /r twice, from an elevated command prompt, the backup started to work again.

Uninstalling Virtual Machine Additions in Hyper-V

The error message "this installer may only be run inside of a virtual machine" appears when you try to remove old virtual machine additions (from Virtual Server 2005/Virtual PC 2004) when running the virtual machine in Hyper-V.

The migration guidelines recommend the removal (but do not mandate it) of the Virtual Machine Additions. But this is probably because later versions of the additions can be removed from inside Hyper-V, earlier versions cannot.

The problem is the existence of this software stops the installation of the Hyper-V Integration Services.

So to remove the Virtual Machine Additions of the Hyper-V guest (that has been previously used in Virtual PC/Server) you need to do the following:

1. Shutdown the Hyper-V virtual guest
2. Share the folder containing the VHD for this guest
3. Install Virtual PC 2007 or later on another computer
4. Create a new virtual guest on the Virtual PC, pointing the VHD property to the shared VHD on the network and do not create undo disks.
5. Boot the Virtual PC guest and uninstall the Virtual Machine Additions. Any prompts about new hardware should be ignored by pressing the Cancel button.
6. The removal process will require a reboot. Once the reboot has completed you can then shutdown the virtual PC.
7. Remove the Virtual PC guest, stop sharing the VHD folder and restart the guest in Hyper-V.
8. Install the Hyper-V Integration Services.

If the virtual guest is so old as to have a Standard PC HAL installed then attempts to install the Integration Services results in the following error "Setup cannot upgrade the HAL in this virtual machine. Hyper-V integration services can be installed only on virtual machines with an ACPI-compatible HAL. For information about hardware requirements, see the Hyper-V documentation".

This cannot be fixed and so if you have an old virtual machine that has a Standard PC HAL (from Device Manager > Computer) then do without the integration services or rebuild the guest from scratch.