Available VM sizes and Images in Azure per location

When creating virtual machines in Microsoft Azure, you’ll need to know which machine size and image to use (provided you’re not using your own uploaded custom image). Microsoft (and partners) did a great job in providing many pre-defined images for the IaaS platform, however not all images are available in all Azure regions. An image could be available in the South Central U.S location, but not in the “Japan East” region. The same applies to the VM sizes, for example, the Standard_NC6 size (backed by a Tesla K80 GPU) is only available in East U.S. and South Central U.S. locations, not in any of the other locations.

To check which VM sizes and images are available in your target location, can easily be done using PowerShell. To get you started with the Azure CmdLets, refer to my previous post.

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Troubleshooting vGPU on XenServer

vGPU on XenServer is awsome technology. But as with any other software, it can happen that you run into issues. For example, when starting a VM which has a vGPU profile assigned, the VM can fail with the dreaded “vgpu exited unexpectedly” error. To be more precise, such an error could read:

Internal error: xenopsd internal error: Device.Ioemu_failed("vgpu exited unexpectedly")

In XenCenter, the log tab will display the following entry:

vGPU error displayed when starting VM
vGPU error displayed when starting VM

In this article, I’ll describe some steps troubleshoot vGPU issues and possible solutions to fix failing vGPU-enabled VMs.

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Upgrading the NVIDIA GRID vGPU driver on XenServer

Last week, NVIDIA released an update for the vGPU driver and manager (also described on The Citrix Blog). Besides bug fixes, this release introduces 3 new vGPU profiles, 1 new profile for the GRID K2 card (K280Q) and 2 new profiles for the GRID K1 card (K160Q and K180Q).

Card Profile Frame buffer Virtual display heads Max resolution per head Max vGPUs per GPU Max vGPUs per board
K1 K180Q 4096Mb 4 2560×1600 1 4
K1 K160Q 2048Mb 4 2560×1600 2 8
K2 K280Q 4096Mb 4 2560×1600 1 2

As you can see, the K180Q and K280Q profiles will assign an entire GPU to a VM. This can be compared to GPU pass-through, but leveriging the functionality of vGPU.

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Fullscreen applications with HDX 3D Pro – Part 3

A few days ago, I wrote a post about Citrix’s fix for fullscreen applications in HDX 3D Pro connections. In that post I mentioned the fact that by default, an application launched in a resolution larger than the session’s resolution, will be trimmed off. Rachel Berry (Product Manager HDX Graphics for XenDesktop/XenApp, twitter @rhbBSE) provided me with some feedback on my article. Especially this part:

I understand why the application behaves in this way. The best way to fix such an challenge is to “scale” the application (I don’t even know if this would be possible programmatically) so that it scales while it maintains the aspect ratio. This way you would always see the entire application, no matter what the resolution is.

One feature of Citrix Receiver, which I knew exists, but never used, is the ability to scale the session completely. I investigated this feature as solution for the trimming of high-resolution applications.

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Fullscreen applications with HDX 3D Pro – Part 2

In my previous post about full screen applications in HDX 3D Pro, I explained possible solutions to the “Full Screen Applications are not supported in Citrix HDX 3D Pro” message. In short, the issue is due to the fact that the application does not use the same resolution as your HDX session.

Full Screen Applications are not supported in Citrix HDX 3D Pro
Full Screen Applications are not supported in Citrix HDX 3D Pro

In the mean time, Citrix release XenDesktop 7.6. The XenDesktop HDX 3D Pro VDA now contains an experimental fix to support full screen applications in any resolution. This fix is explained by Rachel Berry (Product Manager HDX Graphics for XenDesktop/XenApp, twitter @rhbBSE) on the Citrix Blog: http://blogs.citrix.com/2014/10/24/hdx-3d-pro-experimental-support-for-full-screen-apps/

Enable support for full screen applications

As described in Rachel’s blog post, you have to modify the registry on the machine where your VDA is installed. Insert the following value:


To check this feature out, I’ve upgraded my lab environment to 7.6 (both DDC and VDA) and injected the registry value.

Note that this configuration is experimental and currently not officially supported by Citrix.

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Performance impact of HDX 3D Pro in virtual desktop environments

Implementing GPUs in your virtual desktop environment (for example vGPU or GPU pass-though) allows better use of graphical intensive applications (like Catia, AutoCAD, Photoshop, etc.). These applications have an impact on utilization (CPU, memory, disk I/O) in your infrastructure. Not only the applications will impact your infrastructure, sending the graphical intensive data over the LAN or WAN will at least impact your network and the CPU on the end-point and inside your virtual desktop. In this article I will explain the impact on network level.

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Fullscreen applications with HDX 3D Pro

If you’ve been working with GPU deployment in your virtual desktop environment (XenDesktop or XenApp), you probably also installed HDX 3D Pro. Leveraging the GPU, you can use more graphic-intensive applications. Some of these graphic-intensive applications sometimes launch in fullscreen mode by default (think of benchmarking tools or videogames). The result of starting an application in fullscreen mode could be the following error:

Citrix HDX 3D Pro Warning!
Full Screen Applications are not supported in Citrix HDX 3D Pro.
Press Ok to exit.

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Planning GPU deployment in virtualized environments – Part 2

In my previous post, I explained some planning considerations when implementing GPUs in a virtualized environment. There are a few other considerations, especially in terms of hardware, when you implement GPUs in your virtualized environment. This article will contain some of these considerations.

Blade hardware

When planning to implement GPUs in existing hardware, be sure that the current hardware does support the installation of a GPU. If your current environment, for example, consists of blade servers (like Cisco UCS B-series or HP BL series), your environment will not be able to be upgraded with a GPU. This means that you have to invest in new hardware.

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Planning GPU deployment in virtualized environments

Implementing a graphics card in your server allows better performance for GPU-intensive applications in VDI and SBC environments. With Citrix and NVIDIA’s vGPU innovations, this is becoming more popular. However, if you don’t plan your GPU deployment correctly, user acceptance of these new innovations will be difficult. This article will contain some things to keep in mind while planning your GPU deployment in virtualized environment. While I created this article with XenDesktop in mind, it does apply to any other VDI or SBC technology like Vmware View, RemoteFX and XenApp.

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Gathering Performance Data in XenServer for external parsing

If you’re used to working with VMware, you probably know about the nifty little utility esxtop. This tool allows you to view real-time performance data on a ESX host. It also allows you to gather performance metrics in batch mode, which allows you to analyze the data in eg. Excel or ESXplot.

For those who are working with XenServer, a similar utility is available called xentop. The xentop utility allows you to monitor real-time performance metrics, like esxtop does. However, gathering data like in esxtop is a challenge.

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