XenDesktop Management - The following concepts address information needed to properly manage a virtualized desktop environment:
Whether the desktop is a hosted virtual machine-based virtual disk image desktop, a local streamed desktop, or a hosted shared desktop, certain optimizations allow the hardware to focus on end user-related tasks as opposed to extraneous system-related tasks. The following table lists a few specific options you can consider disabling:
Note: For more information about virtual desktop optimizations for Windows XP, see Citrix article CTX124239
Networking Optimizations - The following table lists several network optimizations that you should configure:
Storage Optimizations - You should consider the following when optimizing storage requirements:
Integrated vDisk Versioning - VHD differencing disks are used to represent the different versions of the vDisk image being updated. Using differencing disk files allows you to avoid cloning a full vDisk image every time an update needs to be applied. The differencing disks contain only the changes made to the prior vDisk version, which results in smaller file sizes and reduces the impact to storage.
Support for Distributed vDisk Storage - vDisk storage can be distributed across multiple Provisioning Services hosts or multiple sites. This allows for a single set of vDisks to be managed in one location, either on shared storage or the local disks of the Provisioning Services hosts, and copied to storage used in other locations. A vDisk inventory is maintained on each host using a load-balancing logic to ensure that new streaming sessions are assigned to a server that can access the assigned vDisk files.
vDisk Size - Create vDisks larger than the initial necessary room to allow space for additional application installations and updates. Determine the space requirements for the specific environment. Citrix recommends an estimated vDisk size of 15 GB for Windows XP and 25 GB for Windows 7.
A typical installation of Windows 7 consumes about 6 GB of space, and Windows XP with no local applications consumes between 1 to 3 GB. If installing local applications, Citrix recommends adding 25 percent of the space from the initial image footprint.
Write Cache File - The size of a cache file is unique to each virtual machine and depends on several factors, including the applications used, end user workloads, and restart frequency. A provisioned virtual desktop that is used primarily for text-based applications, such as Microsoft Word and Outlook, and is restarted on a daily basis will have an estimated file cache size of 300-500 MB. If end users require graphic-intensive applications, such as Microsoft PowerPoint or Visual Studio, or if restarts are performed less frequently, cache file sizes can grow much larger.
Citrix recommends that each organization perform a detailed analysis to determine the expected cache file size for their environment.
Multi-GPU Passthrough for HDX 3D Pro - HDX 3D Pro Graphics enables the delivery of high-end 3D graphics applications, such as CAD/CAM and medical imaging applications. These applications take advantage of a graphics card on the XenServer host for 3D rendering and optionally for deep compression of the data stream. The Multi-GPU Passthrough feature of XenServer allows a physical graphics processing unit (GPU) on the host to be mapped to a virtual machine. A XenServer host with multiple GPUs can share the GPUs to an equal number of virtual machines, using a 1:1 ratio. This reduces hardware costs for high-end 3D graphics. Before configuring Multi-GPU Passthrough for HDX 3D Pro, verify that the hardware and software requirements have been met.
You can configure how the virtual CPUs are assigned in terms of sockets and cores. For example, you can configure a virtual machine with four virtual CPUs in the following ways:
- Virtual desktop optimizations
- Virtual desktop updates
- Virtual desktop environment policies
- Virtual desktop creation
- USB device support
Whether the desktop is a hosted virtual machine-based virtual disk image desktop, a local streamed desktop, or a hosted shared desktop, certain optimizations allow the hardware to focus on end user-related tasks as opposed to extraneous system-related tasks. The following table lists a few specific options you can consider disabling:
| Option to Disable |
Description |
| Last access timestamp |
Starting an operating system accesses hundreds to thousands of files, all of which must be updated. Each action requires disk and CPU time that would be better used for end user-related tasks. |
| Screen saver |
A graphical screen saver uses unnecessary memory and CPU cycles when the end user is not using the desktop. Instead, configure the screen to go blank to reduce the memory and CPU consumption. |
| Unnecessary features |
Windows 7 contains components, such as Media Center, Windows DVD Maker, Tablet PC Components, and Games. These applications take memory, CPU, and are graphics intensive. If they are not required in your organization, consider removing the unnecessary services before deploying the virtual machine image. |
Networking Optimizations - The following table lists several network optimizations that you should configure:
| Component | Description |
| Target Devices |
Target devices must be able to dynamically update their Host (A) records in DNS with the IP address they are assigned during the registration process. |
| Desktop Delivery Controllers |
Desktop Delivery Controllers must be able to update their own DNS records in the event that additional Desktop Delivery Controllers are added to, moved, or modified in the environment. |
| Active Directory- integrated DNS |
Integrating Active Directory with the DNS zone allows you to identify which virtual machines can dynamically update their DNS records by using an Access Control List (ACL) and also provides a layer of security for the dynamic updates to take place. |
Storage Optimizations - You should consider the following when optimizing storage requirements:
Integrated vDisk Versioning - VHD differencing disks are used to represent the different versions of the vDisk image being updated. Using differencing disk files allows you to avoid cloning a full vDisk image every time an update needs to be applied. The differencing disks contain only the changes made to the prior vDisk version, which results in smaller file sizes and reduces the impact to storage.
Support for Distributed vDisk Storage - vDisk storage can be distributed across multiple Provisioning Services hosts or multiple sites. This allows for a single set of vDisks to be managed in one location, either on shared storage or the local disks of the Provisioning Services hosts, and copied to storage used in other locations. A vDisk inventory is maintained on each host using a load-balancing logic to ensure that new streaming sessions are assigned to a server that can access the assigned vDisk files.
vDisk Size - Create vDisks larger than the initial necessary room to allow space for additional application installations and updates. Determine the space requirements for the specific environment. Citrix recommends an estimated vDisk size of 15 GB for Windows XP and 25 GB for Windows 7.
A typical installation of Windows 7 consumes about 6 GB of space, and Windows XP with no local applications consumes between 1 to 3 GB. If installing local applications, Citrix recommends adding 25 percent of the space from the initial image footprint.
- Minimize the number of locally installed applications to reduce the vDisk size.
- Maintain as generic a vDisk as possible to use the same vDisk for multiple workloads.
- Deliver personalized applications using XenApp servers or Citrix streaming when possible.
- Consider allocating two-times the disk space required for each maintained vDisk.
Write Cache File - The size of a cache file is unique to each virtual machine and depends on several factors, including the applications used, end user workloads, and restart frequency. A provisioned virtual desktop that is used primarily for text-based applications, such as Microsoft Word and Outlook, and is restarted on a daily basis will have an estimated file cache size of 300-500 MB. If end users require graphic-intensive applications, such as Microsoft PowerPoint or Visual Studio, or if restarts are performed less frequently, cache file sizes can grow much larger.
Citrix recommends that each organization perform a detailed analysis to determine the expected cache file size for their environment.
Multi-GPU Passthrough for HDX 3D Pro - HDX 3D Pro Graphics enables the delivery of high-end 3D graphics applications, such as CAD/CAM and medical imaging applications. These applications take advantage of a graphics card on the XenServer host for 3D rendering and optionally for deep compression of the data stream. The Multi-GPU Passthrough feature of XenServer allows a physical graphics processing unit (GPU) on the host to be mapped to a virtual machine. A XenServer host with multiple GPUs can share the GPUs to an equal number of virtual machines, using a 1:1 ratio. This reduces hardware costs for high-end 3D graphics. Before configuring Multi-GPU Passthrough for HDX 3D Pro, verify that the hardware and software requirements have been met.
You can configure how the virtual CPUs are assigned in terms of sockets and cores. For example, you can configure a virtual machine with four virtual CPUs in the following ways:
- Four sockets with one core for each socket
- Two sockets with two cores for each socket
- One socket with four cores for each socket