Upgrade or Clean Install? Migrating to Windows Server 2008

This article is the first of a 4-part series on the deployment of Windows Server 2008 R2. We'll talk about the options available to move to Windows Server 2008 R2, and what planning and considerations are required for a successful migration.

The Rise of 64-Bit Operating System

As 64-bit hardware is becoming more common due to an increase of memory usage and processing demand in applications, it would be a logical step to focus development solely on 64-bit operating systems instead of supporting both 32-bit and 64-bit architectures. 64-bit architectures allow for more than 4GB of address space for operating system and applications, and they help speed up processing of scientific applications that do a lot of complex numerical analysis. On the business side, the demand for 64-bit hardware is increasing, thus it would be beneficial to focus on developing a better product for the 64-bit customers.

Due changing industry trends, starting with Windows Server 2008 R2, Microsoft has stopped developing a 32-bit Windows Server platform for the public. Yes, you heard it right, but don't get this confused this with Windows 7. Microsoft's latest client-side operating system has both 32-bit and 64-bit flavors, allowing Windows 7 to be installed on older hardware which supports only 32-bit architecture.

What are the implications for IT? Many admins are wondering, "what about the legacy software that runs perfectly fine on x86 platform? What about the old but faithful x86 hardware?" We will be covering these questions later in this section.

Decision Matrix – Clean or Upgrade

With the shift to 64-bit operating systems, IT departments will need to have a different strategy for managing their IT infrastructures. If a server reaches its capacity, do you cluster a new machine, or do you upgrade the server operating system? If the existing server is running with a 32-bit operating system, clean installation is the only option. It is not possible to upgrade the operating system from a 32-bit OS to a 64-bit OS (or vice versa).

The following table will give you an idea of when to do a clean installation of Windows Server 2008 R2, and when to do an upgrade.

Upgrading From a 32-Bit to 64-Bit Operating System

As shown in table 1 above, if the installed operating system is a 32-bit version, it will not be possible to do an upgrade to Windows Server 2008 R2. Cross-architecture, in-place upgrades (for example, x86 to x64) are not possible. In this scenario, the only option is to do a clean installation and migration of the applications and settings to a clean installation Windows Server.