Users will only accept the transition to VDI if the virtual desktops they work with perform at least as well as...
the physical desktops they were accustomed to.
Matching the performance of physical desktops can be a tall order, however, considering that virtual desktops share network resources with one another.
One way to mitigate VDI performance issues is with real-time monitoring, which allows IT to spot and remediate changing conditions before those conditions cause any noticeable problems. This type of rapid detection and response is critical to ensure a good end-user experience, but it is not the only step IT can take.
IT can take steps to configure virtual desktops and alter settings to yield optimal virtual desktop performance.
Boots and logons
One way to minimize performance problems is to eliminate boot storms, which occur when too many users boot their virtual desktops at the same time, often at the beginning of the workday. IT can fight boot storms by configuring the virtual desktops to automatically boot at a time just before the workday begins.
IT can also limit the effects of boot storms by not overprovisioning the virtualization hosts. To do so, IT must ensure that the back-end infrastructure has enough resources in reserve to cope with periods of heavy activity.
On a similar note, IT can set a resource limit for individual desktops to prevent one virtual desktop from using too many resources. For example, IT can use Microsoft Storage QoS -- a program that helps manage and monitor virtual machines -- or similar software to prevent any virtual desktop from consuming too much storage IOPS.
Another step IT can take to reduce logon times and other VDI performance issues is to deploy Microsoft User Experience Virtualization. This tool allows users to keep the same desktop across multiple devices and prevent them from having to rely on roaming profiles.
Roaming profiles require copying profile elements to Windows as a part of the logon process. This process can hinder performance, especially if the profiles are large or if multiple users are logging on simultaneously.
Sharing VDI resources
IT can take action within Windows to make VDI perform better. One option is to disable virtual memory use within the virtual desktops.
By default, Windows moves memory pages to a disk-based pagefile to conserve RAM. This paging operation consumes storage IOPS, diminishing network performance. IT can safely disable virtual memory as long as it provisions the desktop with a sufficient amount of RAM.
IT should create clean operating system deployment images. A default Windows installation is full of bloatware, as well as unnecessary processes and services. Uninstalling software, removing unneeded features and disabling unnecessary services can go a long way toward improving virtual desktop performance.
Turning off OS-level visual effects such as transparency and animation can free up resources, as well. Visual effects may consume a small amount of memory and CPU, but in an organization where users share resources, reclaiming even a few resources can go a long way toward preventing VDI performance issues.
There are a number of maintenance tasks that the OS runs automatically that may be appropriate for physical desktops, but that are a problem with virtual desktops, and that IT should consider disabling. Tasks such as hard disk defragmentation and automated deep malware scans can consume a lot of IOPS, causing VDI performance issues, such as network latency, without delivering any significant benefit in return.
Configuring virtual desktops to receive updates from a Windows Server Update Services server can help limit IOPS usage during updates compared to direct updates from Windows Update. One of the benefits of virtual desktops is that individual desktops don't need to run updates and patches. IT can handle all of these functions from the central image and redistribute the latest version without increasing IOPS consumption.
One last setting to consider is Windows' High Performance power plan. This may sound counter-intuitive, but Windows consumes various hardware resources when it goes into and comes out of hibernation. IT can reduce VDI performance issues by turning off any OS power-saving features.