Using Windows virtual desktops in a server consolidation project

To improve server consolidation ratios, server administrators often tweak virtual machine (VM) configuration and use advanced features such as Microsoft’s Hyper-V Dynamic Memory. But another stone shouldn’t go unturned: Windows virtual desktops.

Even server administrators are sometimes forced to deal with Windows virtual desktops, because every virtual desktop infrastructure (VDI) starts with virtualization at the server level. And some of the best low-hanging fruit for a server consolidation project can lie with your hosted virtual desktops.

Optimizing your desktops’ performance and resource consumption helps squeeze more Windows virtual desktops onto fewer servers. And coupled with desktop cloning, where provisioned VMs start their lives from a specially configured template, the return on investment (ROI) from desktop consolidation can be attractive.

But if you don’t configure clones and their templates correctly, problems with that ROI can creep into your architecture. If you leave some of the default Windows 7 configurations as is, for instance, it can significantly affect how many VMs can run at once. In other cases, tuning a few settings can greatly reduce the resource needs of each Windows 7 VM and improve consolidation ratios.

Using an out-of-box configuration as your desktop template is a well-known bad idea. That’s why each of the three major VDI vendors -- VMware, Microsoft and Citrix Systems -- has released its own guidance on how to tune the OS for better desktop consolidation. These documents include VMware View Optimization Guide for Windows 7, Deploying Microsoft Windows 7 Virtual Desktops with VMware View, and Citrix Windows 7 Optimization Guide for Desktop Virtualization.

In addition to those documents, the following eight tips for configuring virtual desktops can help improve your server consolidation project.

1. Store documents elsewhere. This first tip is as much an educational as it is a technical suggestion. Users in the physical world become accustomed to storing documents on desktops and local computers. But you’ll likely encounter delays when logging into virtual desktops if you store those documents locally. Resources such as storage are also affected if you don’t rethink how you store documents. Storing them on file servers instead of inside profiles will aid your server consolidation project, because it frees up space and allows for greater VM density.

2. Disable unnecessary services. Reading through the three documents above, you’ll find no less than 34 services that are good candidates for disabling. Examples include the Desktop Windows Manager Session Manager, Themes, the Indexing Service, Offline Files and Windows Search. These services make sense on physical desktops but consume resources on virtual ones.

Turning off these services reduces the memory footprint of each Windows 7 instance and eliminates unnecessary activities that affect processor use. Check each service to ensure that it’s not needed in your infrastructure, then shut it down with Group Policy. Your server consolidation project will benefit from having more memory available for Windows virtual desktops.

3. Disable defragmentation. Windows 7 includes built-in defragmentation that’s turned on by default. Defragmenting is great for ensuring disk performance in a long-lived physical instance, but running it in a short-lived VM clone causes more wasted processor cycles than performance benefits. The Windows 7 defragger is also configured via a scheduled task. That means that every running Windows 7 instance could use it simultaneously, creating another performance hit. Ensure that templates are always defragged, then shut down those services for every clone.

4. Un-Aero Windows 7. Windows 7’s Aero interface is beautiful. It makes Windows easier on the eyes and improves the aesthetics of the virtual desktop experience. But it does so while increasing the processor and memory requirements of each OS. That isn’t good for desktop consolidation. Turn Aero off to improve resource optimization in Windows virtual desktops.

5. Stop indexing. Windows 7’s Indexing Service is a smart addition to a laptop or desktop computer full of files. With an index, searching operations take less time and consume fewer resources. But you shouldn’t store files on Windows virtual desktops anyway, so indexing shouldn’t be necessary. Turning off this OS function will further help your server consolidation project.

6. Update your template, not your clones. Microsoft releases updates on a monthly basis, so Windows virtual desktops need patching every month. But updating the clones defeats the purpose of having clones and adds to the resources needed to run each clone. A better solution is to update only the template during those regular patch cycles and then regenerate the clones. If clones don’t require additional resources, desktop consolidation can become easier.

7. Turn off screen savers. This tip has been around since the first virtualized servers, but it is even more important for virtual desktops. Screen savers are a huge processing power waste. Those with more spinning graphics are worse than those with less, but none are a good idea for getting the best desktop consolidation.

8. Disable system restore. When it’s enabled on Windows virtual desktops and servers, system restore is another feature that can save an administrator from working weekends . Yet the cloning infrastructure you’ve set up for virtual desktops provides essentially the same function. Get rid of those unnecessary resources and turn off the system restore function when it’s not needed.

Take a look at a combination of the vendors’ guidance to ensure that you get the best desktop consolidation out of your Windows virtual desktops.

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