Month: July 2011

XenServer 6.x makes it possible of passthrough of multiple GPU’s.

HP blade workstation WS460C is an enterprise solution for this area that fits perfect with Citrix XenServer 6.x multiple GPU passthrough. You can attach an Graphic Expansion to the WS460C so its possible to integrate two graphic cards like (Nvidia FX3800, FX4800, FX5800 or the new fermi cards 4000, 5000, 6000)

The target here is to support high-end 3D professional graphics applications with multiple GPU passthrough. Applications like Autodesk/Dassualt Systems and many more CAD/CAM systems are often using OpenGL and or Direct-X and Citrix provides the full user experience with HDX3D to deliver this everywhere. HDX3D is available both for XenDesktop 4/5.x> and XenApp 5/6.

This article descripes HowTo enable MultiGPU with HP blade workstation WS460C with HP Graphic Expansion blade and Citrix XenServer 6.x

Bios Settings for ws460cG6 with Graphics Expansion Blade

Option “HP Graphics Expander x16”
Help (F1 pressed) associated to this option

“When enabled will allow x16 PCIe connection on HP Graphics Expander slot 1.  Slot 2 will NOT be functional”

HowTo enable MultiGPU in HP WS460c with Graphic Expansion blade

Choose this BIOS setting for “HP Graphics Expander x16” for enabling both graphic cards. When the BIOS setting is disabled the Citrix XenServer 6.x is able to see both Graphic cards and you can then passthrough the GPU’s to the Virtual machines.

HP Graphics Expander x16: DISABLED

  • HP Graphics Expander slot 1 : x8
  • HP Graphics Expander slot 2 : x8

 Enabling “VT for direct I/O” in the BIOS

HowTo identify the Multiple GPU’s in Citrix XenServer 6.x

Note XenServer 6.x XenCenter Console only shows 1 GPU if you have multiple GPU’s *this is default design belowed explains why:

If you have multiple GPUs in different PCI slots then Xenserver forms the groups of identical GPUs. For example if you have 2 – Quadro 4000 GPUs then there will be one Quadro 4000 GPU group identified by Xenserver.

Now when you try to assign the GPU to a VM from Xencenter it shows the GPU group and not the individual GPU. In your case one GPU group has 2 – Quadro 4000 cards, so you can assign this GPU group to 2 VMs wherein each GPU is attached to an individual VM

If you want to identify that XenServer 6.x is showing multiple GPU’s access local command shell

Execute #lspci to view multiple  GPU’s
In belowed picture you can see i have identified 2 GPU’s with the command #lspci

New features in Citrix Provisioning Services 6.0

The Provisioning Services 6.0 Beta provides an early opportunity for citrites, customers and partners to try the new features in this release.  This release focuses on providing tools to streamline the image management process, including:

  • Integrated vDisk Version Management: Allows you to create and manage versions directly within the Provisioning Services Console. Versions can be targeted specific groups of devices facilitating the image lifecycle flow through maintenance, test, and production. In addition, versions are maintained as difference files, conserving storage space.
  • Automated vDisk Updates: Allows you to define recurring scheduled tasks that automate the process of vDisk patching using tools like Microsoft System Center Configuration Manager (SCCM) and Windows Server Update Services (WSUS).
  • Support for vDisk Replication: Allows you to safely use replication solutions like Microsoft DFS Replication to distribute vDisks across multiple servers or geographic locations. Provisioning Servers will maintain an inventory of available vDisks and versions and adjust load balancing as needed to ensure sessions are only assigned to servers that have access to the required vDisk/version.

The beta will run through July and August and is open to Citrix partners and existing customers who have Provisioning Services licenses, or Enterprise or Platinum XenDesktop, XenApp, or XenServer licenses. Provisioning Services 6.0 is compatible with XenDesktop 5 and SP1, XenApp 6, and XenServer 5.6, FP1, and SP2.

Click here to download the Provisioning Services 6.0 Beta

Before installing the beta, please read through the release notes.  They will provide you with information about what functionality is and is not available in the beta.

During the beta you can go to the Provisioning Services 6.0 Beta Forum to get updated information about the beta, post questions or problems, and get help from members of the Provisioning Services team and other beta participants.

Deep dig-in Citrix Provisioning Services 6.0

Check out this cool presentation that Patrick Carey made at Citrix Synergy in SF 2011

My Experience with Citrix Provisioning Services 6.0 Beta (updated 07-07-2011)

I have just downloaded and installed the Citrix Provisioning Services 6.0

  • The installer looks great, you can now install the server with console, even if you installed the console first. This was an issue  before in later versions.
  • Upgrading from Citrix Provisioning Services 5.6SP1 to 6.0 Beta runs smooth
  • Citrix Storage controllers is a device software i noticed thats new, “windows security pops up ..”
  • i keep you updated when i see some stuff in PVS6Beta that i want to share with you*


Although Citrix Systems supports Microsoft Windows Server 2008 R2 SP1 with Citrix XenApp 6, users of Microsoft Server 2008 R2 SP1 must be aware of certain issues when using it in conjunction with this product as outlined in CTX122601 – Microsoft Windows Server 2008 R2 – Known Issues

You cannot connect to Citrix sessions when Microsoft Windows Server 2008 R2 SP1 is present.

Trying to use the quick launch tool CTX122536 – Citrix Quick Launch to the server IP address hung at: “Connection established. Negotiating capabilities…”

“Qwinsta” from a command line returned no information and just left a blinking cursor.

Svchost.exe crashes in TermService

Trying to use the quick launch tool to launch a published application hangs at “launching.”

Note: When verifying this issue against the release to manufacturing of Microsoft Windows Server 2008 R2 SP1, the reviewer was unable to install the Citrix Hotfix XA600W2K8R2X64001 on this unstable server. The windows installer seems to hang, but upon restarting the server, the hotfix is installed.


Install Citrix Hotfix XA600W2K8R2X64026, CTX127360 – Hotfix XA600W2K8R2X64026 – For Citrix XenApp 6.0 for Windows Server 2008 R2 – English

More Information

When connecting to a server running Windows Server 2008 R2 with Service Pack 1, Terminal Services can exit unexpectedly. This causes users to experience a black screen when logging on and the logon process fails to complete. [#232329]


When shadowing a published desktop with a resolution greater than or equal to 1280×1024, the session of the user who is shadowing might terminate when the ICA session Window is resized. A dialog box stating “Virtual Driver error” error message might also be displayed to the user.


The client disconnects because it cannot accept the value of Thinwire Cache Power proposed by the server because the value exceeds the default limits of the client.


You need to increase the value for the Thinwire Cache Power.

Warning!!!: Using the Registry Editor incorrectly can cause serious issues with the operating system that might require you to reinstall the operating system. Citrix does not guarantee that the issues resulting from the incorrect use of Registry Editor can be resolved. Use the Registry Editor at your own risk. Ensure that you make a backup of the registry before you edit it.

On the endpoint of the user who is shadowing, create the Tw2CachePower value under the following registry key:

HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\ICA Client\Engine\Configuration\Advanced\Modules\Thinwire3.0

The following are the details of the registry key:

  • Value: Tw2CachePower
  • Type: REG_SZ
  • Data: 19 – 25

Even though the maximum value specified for Tw2CachePower is 25, a value of 24 covers most scenarios. The client device must be able to allocate the memory of 2^24 bytes, if cache power of 24 is used.

If you are shadowing from a XenApp 6 published Desktop, then you need to add the Tw2CachePower value under the following key:

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Citrix\ICA Client\Engine\Configuration\Advanced\Modules\Thinwire3.0

Citrix have released Virtual Driver Channel tool for XenApp and XenDesktop environments.


This tool provides the ability to pass the end client information to a XenApp application in XenApp / XenDesktop environments. The tool creates a virtual channel between a XenDesktop VDA and a XenApp server session. The virtual channel driver on the VDA monitors the status of client connections and sends notifications when a client connects or disconnects to the VDA. XenApp applications can use provided APIs to collect end client information or status.


Install an ICA client before installing VDCLNTINFO.msi on the XenDesktop client. The current release of the vdclntinfo setup does not have dependency checking, and requires the ICA client to be installed first.

Installing Virtual Driver Channel

Install an ICA client before installing VDCLNTINFO.msi. Install VDCLNTINFO.msi. Kill wfcrun32.exe if it is running.

How to Test Virtual Driver Channel

To Verify that it is working: Copy ctxclntinfo.exe to a XenApp Server. Connect to a XenDesktop that has VDCLNTINO.msi installed. Launch a XenApp CMD session or a published desktop from the XenDesktop VDA. Run ctxclntinfo.exe. It should output the client name and IP address. Run ctxclntinfo.exe /loop. It will wait on client connect/disconnect notifications. You can now disconnect from the VDA and reconnect to the VDA from a different client. The demo application outputs the new client information.

How To Use Virtual Driver Channel

See README.pdf for APIs associated with the tool.


Download Virtual Driver Channel here