Beginning the Migration Process

Any migration procedure should define the reasons for migration, steps involved, fallback precautions, and other important factors that can influence the migration process. After finalizing these items, the migration can begin.

Identifying Migration Objectives

Two underlying philosophies influence technology upgrades, each philosophy working against the other. The first is the expression "If it ain't broke, don't fix it." Obviously, if an organization has a functional, easy-to-use, and well-designed Windows 2000 infrastructure, popping in that Windows Server 2003 CD and upgrading may not be so appealing. The second philosophy is something along the lines of "Those who fail to upgrade their technologies perish."

Choosing between these two philosophies effectively depends on the factors that drive an organization to upgrade. If the organization has critical business needs that can be satisfied by an upgrade, such an upgrade may be in the works. If, however, no critical need exists, it may be wise to wait until the next iteration of Windows or a future service pack for Windows Server 2003.

Establishing Migration Project Phases

After the decision is made to upgrade, a detailed plan of the resources, timeline, scope, and objectives of the project should be outlined. Part of any migration plan requires establishing either an ad hoc project plan or a professionally drawn-up project plan. The migration plan assists the project managers of the migration project accomplish the planned objectives in a timely manner with the correct application of resources.

The following is a condensed description of the standard phases for a migration project:

• Discovery The first portion of a design project should be a discovery, or fact-finding, portion. This section focuses on the analysis of the current environment and documentation of the analysis results. Current network diagrams, server locations, WAN throughputs, server application dependencies, and all other networking components should be detailed as part of the Discovery phase.

• Design The Design portion of a project is straightforward. All key components of the actual migration plan should be documented, and key data from the Discovery phase should be used to draw up Design and Migration documents. The project plan itself would normally be drafted during this phase. Because Windows Server 2003 is not dramatically different from Windows 2000, significant re-engineering of an existing Active Directory environment is not necessary. However, other issues such as server placement, new feature utilization, and changes in AD replication models should be outlined.

• Prototype The Prototype phase of a project involves the essential lab work to test the design assumptions made during the Design phase. The ideal prototype would involve a mock production environment that is migrated from Windows 2000 to Windows Server 2003. For Active Directory, this means creating a production domain controller (DC) and then isolating it in the lab and promoting it to the Operation Master (OM) server in the lab. The Active Directory migration can then be performed without affecting the production environment. Step-by-step procedures for the migration can also be outlined and produced as deliverables for this phase.

• Pilot The Pilot phase, or Proof-of-Concept phase, involves a production "test" of the migration steps, on a limited scale. For example, a noncritical server could be upgraded to Windows Server 2003 in advance of the migration of all other critical network servers. In a slow, phased migration, the Pilot phase would essentially spill into Implementation, as upgrades are performed slowly, one by one.

• Implementation The Implementation portion of the project is the full-blown migration of network functionality or upgrades to the operating system. As previously mentioned, this process can be performed quickly or slowly over time, depending on an organization's needs. It is subsequently important to make the timeline decisions in the Design phase and incorporate them into the project plan.

• Training and Support Learning the ins and outs of the new functionality that Windows Server 2003 can bring to an environment is essential in realizing the increased productivity and reduced administration that the OS can bring to the environment. Consequently, it is important to include a Training portion into a migration project so that the design objectives can be fully realized.

For more detailed information on the project plan phases of a Windows Server 2003 migration, refer to Chapter 2, "Planning, Prototyping, Migrating, and Deploying Windows Server 2003 Best Practices."

Comparing the Inplace Upgrade Versus New Hardware Migration Methods

Because the fundamental differences between Windows 2000 and Windows Server 2003 are not significant, the possibility of simply upgrading an existing Windows 2000 infrastructure is an option. Depending on the type of hardware currently in use in a Windows 2000 network, this type of migration strategy becomes an option. Often, however, it is more appealing to simply introduce newer systems into an existing environment and retire the current servers from production. This technique normally has less impact on current environments and can also support fallback more easily.

Determining which migration strategy to use depends on one major factor: the condition of the current hardware environment. If Windows 2000 is taxing the limitations of the hardware in use, it may be preferable to introduce new servers into an environment and simply retire the old Windows 2000 servers. If, however, the hardware in use for Windows 2000 is newer and more robust, and could conceivably last for another two to three years, it may be easier to simply perform inplace upgrades of the systems in an environment.

In most cases, organizations take a dual approach to migration. Older hardware is replaced by new hardware running Windows Server 2003. Newer Windows 2000 systems are instead upgraded in place to Windows Server 2003. Consequently, auditing all systems to be migrated and determining which ones will be upgraded and which ones retired are important steps in the migration process.

Identifying Migration Strategies: "Big Bang" Versus Slow Transition

As with most technology implementations, there are essentially two approaches in regard to deployment: a quick "Big Bang" approach or a phased, slower approach. The Big Bang option involves the entire Windows 2000 infrastructure being quickly replaced, often over the course of a weekend, with the new Windows Server 2003 environment; whereas the phased approach involves a slow, server-by-server replacement of Windows 2000.

Each approach has its particular advantages and disadvantages, and key factors to Windows Server 2003 should be taken into account before a decision is made. Few Windows Server 2003 components require a redesign of current Windows 2000 design elements. Because the arguments for the Big Bang approach largely revolve around not maintaining two conflicting systems for long periods of time, the similarities between Windows 2000 and Windows Server 2003 make many of these arguments moot. With this point in mind, it is more likely that most organizations will choose to ease into Windows Server 2003, opting instead for the phased migration approach to the upgrade. Because Windows Server 2003 readily fits into a Windows 2000 environment, and vice versa, this option is easily supported.

Migration Options

As previously mentioned, Windows Server 2003 and Windows 2000 "play" together very well. The added advantage to this fact is that there is greater flexibility for different migration options. Unlike migrations from NT 4.0 or non-Microsoft environments, the migration path between these two systems is not rigid, and different approaches can be used successfully to achieve the final objectives desired.