Sep 21 2010

Desktop Refresh: Choosing the Right Master Image

These tips can help you decide when to use thick or thin images during a desktop deployment.

If you're planning your next desktop deployment refresh cycle, you're probably thinking about how to build, deploy and maintain your desktop images. Most organizations have traditionally preferred to deploy a standard, enterprise desktop configuration for their employee PCs to reduce end-user training and support costs. Organizations migrating their desktops to Windows 7 will want to do the same, but the question arises: Should we use thick or thin images to do this?

A thick image is one that has your core business applications preinstalled on it. Thick images may also have other preinstalled components such as language packs, drivers and critical security updates. Thin images on the other hand have no applications preinstalled, and instead rely on other means for installing applications and possibly other needed components. Both thick and thin images might also include various desktop customizations, such as a standard desktop background or screensaver. The following are a few tips to help you decide between using thick or thin images for your deployment.

Minimize Employee Downtime

Consider using thick images if you want to ensure that core business applications are available to users immediately the first time they log on to their new or upgraded computers. Many organizations include core applications such as Microsoft Office and popular utilities like Adobe Acrobat Reader in their standard images so that these applications are available to users when they first start their computers. Antivirus scanning software is also often included on such images so that the computers are protected from malware immediately after deployment.

Be Considerate of Slow WAN Links

Consider using thin images if you need to transfer standard images to remote branch offices over slow WAN links. Thick images are large and can swamp a slow link and block other important traffic between branch offices and headquarters. And because thick images contain more than thin images, they typically need more frequent updating, which means you'll probably need to transfer them more frequently over the WAN link.

When There's No Systems Management Software

Consider using thick images if your organization doesn't have any systems management software deployed in its infrastructure. When you use thin images, you first deploy your customized operating system to your target computers, together with any necessary drivers and updates. Then use your systems management software, such as Microsoft System Center Configuration Manager, to deploy applications to these systems (see Figure 1). Note, however, that deploying applications this way can take much longer than embedding them within a thick image. If you don't have such systems management software deployed, you are probably better off using thick images instead of thin. Of course, you could try deploying applications using Group Policy Software Installation, but this approach is not as scalable or easy to maintain as using Configuration Manager.

Figure 1: Using System Center Configuration Manager together with thin images 

Remote Desktop Services Environment

Consider using thin images if you have a Remote Desktop Services or Terminal Services infrastructure deployed for delivering applications to your users. RDS lets you run end-user applications centrally on a server and deliver the remote application's user interface (or an entire remote desktop) to the user by using the Remote Desktop Protocol. This means applications don't have to be installed on each user's computer — an ideal scenario for using thin images for desktop deployment. Another environment where thin images can be a good choice is if you use Microsoft Application Virtualization to deploy applications to users' desktops.

Unchanging Environment

Finally, consider using thick images if your environment is simple and doesn't change much. For example, if all of your users need the same suite of applications and they all speak and use the same language, thick images may be a good choice. Just be sure to allocate more of your IT budget toward image maintenance because thick images are typically more work to maintain than thin ones. Also remember that deploying any applications to users who don't actually need them may cause your agency to incur unnecessary licensing costs.