A first step in choosing the best operating system is determining the nearest equivalent to what you are now running. The Web Edition is a completely new edition, and so it doesn’t have an equivalent in the Windows 2000 family of operating systems. The other Windows Server 2008 R2 operating systems map directly to existing Windows 2000 operating systems, as shown in Table 1.
Windows 2000 Server hardware may not be able to support Windows 2008. Assuming a particular server does meet the requirements for 2008, upgrading Windows 2000 to 2008 or R2 is a two step process: Upgrading from Windows 2000 Server to Windows 2003 SP2 and then to Windows 2008. Given the scope of changes between Windows 2000 Server and Windows Server 2008 such an upgrade process is not recommended. (Because Windows Server 2008 R2 is 64-bit only, it is not possible to upgrade from Windows 2000 Server to Windows Server 2008 R2 – even “through” Windows Server 2003.)
In terms of migrating a workload from an older server to a newer server running Windows Server 2008 or R2, in some cases it may be possible to migrate, easing the transition by preserving settings and configuration. Because server roles were introduced after Windows 2000 Server – and given the scope of changes and enhancements to server capabilities over the past 10 years – such a migration path would also, in many cases, involve moving first to Windows Server 2003 and then to Windows Server 2008 or R2.
Given the complications – whether upgrading or migrating – of attempting to move “through” Windows Server 2003 on the way to 2008 or R2 in these scenarios, they are not recommended. A clean install of Windows Server 2008 or R2 – typically on new server hardware is generally recommended.
For a comprehensive list of hardware and software supported by the Windows Server operating system, see the Windows Server Catalog at http://www.microsoft.com/windows/catalog/server/.
Active Directory Considerations
The Active Directory service is an essential and inseparable part of the Windows Server network architecture that provides a directory service designed for distributed networking environments.
Because of this central role – and the complexities involved in selecting a Domain Functional Model – and updating that model at the right point in the migration process from Windows 2000 Server to newer versions of Windows Server, this paper will consider Active Directory at some length.
Active Directory provides a single point of management for Windows-based user accounts, clients, servers, and applications. It also helps organizations integrate systems not using Windows with Windows-based applications and Windows-compatible devices, thus consolidating directories and easing management of the entire network operating system. Companies can also use Active Directory to extend systems securely to the Internet. Active Directory thus increases the value of an organization's existing network investments and lowers the overall costs of computing by making the Windows network operating system more manageable, secure, and interoperable.
Active Directory plays such an important role in managing the network, that as you prepare to move to a newer version of Windows Server, it is helpful to review the new features of the Active Directory service.
The upgrade to Active Directory can be gradual and performed without interrupting operations. If you follow domain upgrade recommendations, it should never be necessary to take a domain offline to upgrade domain controllers, member servers, or workstations.
In Active Directory, a domain is a collection of computer, user, and group objects defined by the administrator. These objects share a common directory database, security policies, and security relationships with other domains. A forest is a collection of one or more Active Directory domains that share the same class and attribute definitions (schema), site and replication information (configuration), and forest-wide search capabilities (global catalog). Domains in the same forest are linked with two-way, transitive trust relationships.
To prepare for upgrades in a domain containing Windows 2000 domain controllers, it is recommended that you apply Service Pack 2 or later to all domain controllers running Windows 2000.
Before upgrading a domain controller running Windows 2000 to Windows Server 2003, or installing Active Directory on the first domain controller running Windows Server 2003, ensure that your server, your forest, and your domain are ready.
Two command-line tools are helpful in upgrading domain controllers:
Winnt32. Use Winnt32 to check the upgrade compatibility of the server.
Adprep. Use Adprep on the schema operations master to prepare the forest. Running Adprep on the schema master updates the schema, which in turn replicates to all of the other domain controllers in the forest.
Note that until you have used Adprep to prepare the forest and the domains within the forest, you cannot upgrade domain controllers running Windows 2000 to Windows Server 2003, or add domain controllers running Windows Server 2003 to Windows 2000 domains.
With the new Active Directory features in Standard, Enterprise, and Datacenter editions, more efficient administration of Active Directory is available to you.
Some new features are available on any domain controller running a newer version of Windows Server, while others are only available when all domain controllers of a domain or forest are running newer versions of Windows Server.