I wanted to provide you with what we (myself, Nicholas Rintalan, Doug Demskis and Dan Allen) figure is a reasonable estimation for resource allocation for Windows 7 and Windows XP desktops when delivered in the hosted VM-Based virtual desktop model (or VDI for short).

See anything shocking? How about 1.5 GB of RAM for light Windows 7 users? Remember, we are talking about the typical implementation that we have seen. That means the desktop image includes antivirus agents, malware agents, monitoring agents and line-of-business applications. These agents and applications add up (especially Line-of-Business apps). Even though the user is a light user, that means they only run 1 or 2 applications. However, those applications are more than Microsoft Word. They are the main Line of Business application. So even though they don’t hit the CPU hard, they still consume a lot RAM (of course these implementations could just put the line of business app on XenApp and not worry about providing a true Windows 7 desktop for light users).

Are you wondering what defines the four groups of users? Here is how we define them:

I’m hopeful that as you start planning your XenDesktop environment, you use realistic approximations on your virtual desktop specifications.

If you want to know more about resource allocation as well as many other areas for planning a XenDesktop environment, then sign up for the XenDesktop Design Handbook. This helps guarantee that you have the latest and greatest design information available.

Daniel – Lead Architect

What you will also see is that other optimization guides probably have many, many more optimizations. Why? Most guides are looking at performance as opposed to the user experience. The settings within this guide are trying to balance the user experience with performance. Some optimizations will make the system run faster without impacting the users while other settings might improve performance might create negative perception. It is a fine line to walk and it is something each person has to determine when building their virtual desktop environment on Windows 7.

If you want the Windows 7 Optimization Guide for XenDesktop, as well as so much more, then access the XenDesktop Design Handbook.

Daniel – Lead Architect

I don’t know about you, but I love the Recycle Bin. Just in case I accidently delete something, I know that I can get it back. But because many different virtual desktop implementations delete modifications upon reboot (Provisioning services included), the general recommendation is to disable this wonder feature of Windows. Think about your desktop experience. Have you ever accidently deleted a file and tried to restore it within a few minutes or hours? I have, and it saved me many times. What if I took this feature away? I don’t know about you but I would be mad as hell.

With Provisioning services, the recycle bin is cleared upon each reboot, but does that mean we shouldn’t allow users to have this functionality within their current desktop session? Unfortunately, the XenConvert optimization utility also disables the recycle bin functionality, but I typically don’t stick to the defaults. I don’t recommend it. I deselect it. And I think if you are really a desktop user and focused on the user experience, you will likely do the same.

Daniel – Lead Architect

• Ron Oglesby’s assessment
• Project VRC’s Deep Dive

What have I learned? You will get minimal performance gains IF you optimize while still providing enough usability for users. Also, if you optimize too much you end up destroying the user experience. I posted a comment on the Project VRC’s recommendations to disable Windows Search. It is true that Search does take some resources, but I find search quite useful within my Office applications. For my virtual desktop implementation, if I disable Search, then I can no longer search within Outlook. Others told me their search still works, albeit slower. Why the difference? Because we included different optimization settings within our virtual desktop environment. We did this to try and improve scalability and performance, but now we have another issue… Troubleshooting.

Because we have done different optimizations, some of which are pretty arcane, we now have different effects on the desktop, and not in a good way. So what does this mean? It means the more optimizations you make, the greater the risk for issues and the harder it will be to troubleshoot. This is what I started calling Feller’s Law: “The more tweaks made, the greater risk for issues.”

Does this mean we shouldn’t be doing any optimizations? No, that is just crazy. There are some things we should disable in a desktop virtualization environment. All that I’m saying is that we need to understand what each optimization might do to the user experience, because the user experience will determine success and failure. And making every possible tweak to the environment isn’t really necessary either as many will have limited impact on the infrastructure.

What will you recommend for your virtual desktop environments?

Daniel – Lead Architect

Most users want to personalize their desktop. They want to configure their own backgrounds. They want to configure their themes. They want desktop sounds to alert them of email messages. So why are we recommending that we disable all of these features?

To save resources. Yes. That is the answer, but is it a good strategy? Disabling this functionality will save some network and system resources but the cost is user acceptance. User acceptance is going to make or break the desktop virtualization solution. You don’t believe me? Look at your own desktop. Did you customize the background? Sounds? Themes? What else? What would you say if you couldn’t do these things?

What would you say if Microsoft or Apple lacked this personalization functionality? They wouldn’t hear the end of it. They would be criticized by every person that touches the OS. So why am I seeing so many Windows 7 optimization guides recommend doing just that?

There is nothing wrong with optimizing the desktop, but these optimizations should not impact the overall acceptance level from our users.

Daniel – Lead Architect

You remember long ago when fancy screen savers were all the rage? You remember the flying toasters right (if not either I’m too old or you are too young)? What about the fish swimming leisurely across your big (14 inch) CRT monitor? We don’t put as much thought into screen savers as we used to, but they are still there. Most of us simply use the default ones within Windows 7, that is, if we have one at all. But what does the screen saver have to do with virtual desktops? Actually, screen savers have a lot to do with desktop virtualization, especially in the hosted VM-based VDI model (at least if you are trying to optimize your environment).

First, the value of the screen saver is that it locks your desktop after so many minutes (assuming you configured it that way). In fact, many types of organizations have guidelines on how long the desktop can remain unlocked for fear of people seeing sensitive data like medical records, financial records, or even a cheesy poem you are writing to your significant other. Using a screen saver that does crazy things on your monitor is like watching videos constantly on your desktop. This not only consumes a massive amount of bandwidth but it also consumes valuable CPU resources. Remember, we are using virtualized desktops. We are sharing CPU resources with other users (check this out to see screen saver’s impact on CPU). We use network bandwidth to deliver screen updates to the end point. Seems a little crazy to do all of these things when chances are high no one is around to view them. So what’s the solution? Don’t use them. Well that is a little harsh, but try to do the following:

• Within the virtual desktop, use an Active Directory group policy to
  • Enable the screen saver
  • Prevent changing the screen saver
  • Password protect the screen saver
  • Set Screen saver timeout
  • Force specific screen saver (Blank screen saver is “scrnsave.scr”)

No bandwidth and no CPU consumed. What if there is massive outrage from the users because they can’t configure their flying toasters anymore? How about doing the following

• Use the end point device’s screen saver to give the user the fancy graphics but keep the virtual desktop as the blank screen saver. User is happy, the network is happy, the CPU is happy. Everyone is happy (well, maybe not those toasters) J

Honestly, if there is this much hysteria around the screen saver, people might have too much time on their hands. In the end, disabling the fancy screen savers is a huge savings you don’t want to miss out on. Remember though, that even if you enable the user password to come out of the screen saver, if the user still has an active connection to Web Interface on their end point, anyone can simply click on the desktop icon and be logged back in. So make sure your Web Interface timeouts are in line with your screen saver timeouts.

Now, time to watch my toasters fly.

Daniel – Lead Architect

Citrix XenDesktop and HDX are smart enough to not send the screen updates for the mouse image to the endpoint, instead they just send coordinates.  Saves a lot of time if you think about how many pixels the mouse takes.  But if you enable the mouse shadow (which is enabled by default), we are talking a different story.  The shadow pixel changes must be sent across the wire because it isn’t just a shadow, it is a blending with the image on the screen.  If you truly are interested in optimizing your Windows 7 desktop virtualization images, then disable the mouse shadow.

It’s pretty easy to do, just go into your mouse properties and deselect “Enable pointer shadow”.

Of course there are always other approaches. You can also go into Performance Options and unselect “Show shadows under mouse pointer” as shown in the next picture. You might want to disable many of these other options as well now that you are here.

But these changes only set the optimizations for the user.  This is a good way to test to see which options are the ones you want to disable, but not a good way to implement globally.  That is where group policies come in. Unfortunately, Microsoft doesn’t provide policies for these items, but you can use a GPO to set the registry values.  The first value you need to set is to allow for customization of the performance options.  This is done by creating a user-based GPO that sets the following registry key:

• Key: HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\VisualEffects
• Value Name: VisualFXSetting
• Value Type: dword
• Value data: 3

Second, you need to set the user preference mask. The value is binary and each option within the previous picture changes the bit value.  What I recommend is you manually set the configuration you want, look up the binary registry key, and then use a GPO to apply that to other Windows 7 virtual desktops. The GPO setting would be

Two keys to better optimize Windows 7.

Daniel – Lead Architect

As I learn more from upcoming Windows 7 implementations, I’ll be updating the following tables, so it might be worthwhile to stay updated with RSS or subscribe via Email. Now, for the good stuff…

Recommended Configurations

The following registry changes are recommended for all deployment scenarios and would almost always be desirable in a Windows 7 hosted VM-based VDI desktop implementation:

Note: The Optimizer column indicates whether this registry change is included in the XenConvert Optimizer tool that is installed with the Provisioning Services target device software.

Standard Mode Recommended Configurations

The next set of registry changes are recommended for images deployed using standard mode vDisk images with Citrix Provisioning services. Standard mode images are unique in that they are restored to the original state at each reboot, deleting any newly written or modified data. In this scenario, certain processes are no longer efficient. These configurations may also apply when deploying persistent images and in many cases should be implemented in addition to the changes recommended in the preceding section.

Optional Configurations

This last set of machine-based registry changes is optional regardless of whether the image is deployed as a persistent or standard image. In many cases, the following configurations should be implemented; however, these configurations should be analyzed for suitability to each unique environment.

Note: These are only recommendations. You should implement these at your own risk

Daniel – Lead Architect

Let’s assume you are using XenDesktop and Provisioning services single image management. That means changes made during the user session are deleted upon reboot.  If we keep that in mind, we have a better idea of what services we can disable because their value is severely diminished if changes are not stored across reboots.  Additionally, there are some services we don’t need or want in our corporate environment and others we don’t think are important but our users definitely want.

You agree? Disagree? Any other services we should shut down?

Daniel - Lead Architect

Of course there are some differences. For example, regardless of the path you are taking, most organizations will create their “Corporate Desktop Image”. At its core, the standard desktop image would have similar configurations like removing games, disabling Media Center, adding anti-virus software, etc. This would be done if Windows 7 were on a traditional desktop or on a virtual desktop.  But on the virtual desktop we will likely do more. We will likely do things like:

• Disable unused Windows services
• Modify the behavior of the Defragmentation subsystem
• Disable the Background Layout Service after it has executed once
• Clean and optimize the image before deployment

Not only that, but with a virtualized Windows 7 environment we will also modify certain aspects to provide greater responsiveness for the user. These are important in certain FlexCast instances where the user is not sitting in front of the Windows 7 desktop.    What optimizations am I talking about?  How about the shadow of your mouse?  Did you even know your mouse had a shadow.  Honestly, I didn’t.  But simply disabling this little feature can provide greater responsiveness for the user.

These are the things I’ve been gathering from our Windows 7 deployments.  These lessons learned will help you on your way to Windows 7.  These are the things I am excited to be discussing during my BriForum session next week in Chicago.     I hope to see you there.

Daniel - Lead Architect