In general, role migration is defined as upgrades of a server’s services from one version of an operating system to another—for example, from Windows Server 2008 to Windows Server 2012. Migration planning depends primarily on the roles you need to migrate. Migrating AD DS requires different planning and execution than migrating File Services or other roles.
Migrations retain settings and configuration and can be used to move from physical to virtualized installations of Windows.
Because Windows Server 2012 is x64-based architecture, you can migrate only from x64-based servers. If the server isn’t x64-based, migration isn’t possible and the server will need to have a clean install, after which the role can be configured for that server.
Windows Server Migration Tools provide a set of Windows PowerShell cmdlets to facilitate the migration of roles. You can install these as a Feature in Windows Server 2012. Windows Server Migration Tools can be used to migrate between the following editions of Windows Server:
- Windows Server Foundation
- Windows Server Standard
- Windows Server Enterprise
- Windows Server Datacenter
The Windows Server Migration Tools are added to the Windows PowerShell command line with the following command:
Add-PSSnapin Microsoft.Windows.ServerManager.Migration
After that snap-in is added, the migration-related cmdlets are available, specific to the type of migration being performed. As previously stated, planning for migration depends largely on what roles are being migrated. However, some steps are common to all role migration planning:
- Identifying source and destination servers
- Installing all critical updates to the source server
- Ensuring that both the source and destination servers have the same number of network adapters
- Preparing a migration store file location that source and destination servers can both access
There are also tasks related to specific roles. The following planning steps are involved in select role migration scenarios.
Planning migration of AD DS and DNS
1. Introduce Windows Server 2012 into the domain so that the existing forest and domain are prepared.
2. Ensure that the destination server meets the hardware requirements for the hosting Active Directory roles.
3. Create an Active Directory backup of the source server.
4. Install Windows on the destination server, using a temporary name and IP address because both will be changed later.
5. Ensure that the source DNS server is running correctly, as discussed in the "Migrating server roles" section.
Planning migration of File Services servers
1. Install Windows on the destination server.
2. Ensure that the time and date are synchronized with the source server.
3. Match the same File Services features on both the source and destination servers.
4. Open TCP and UDP port 7000 on any network resources or firewalls between the source and destination servers.
5. Verify that the destination server has enough free disk space and that any quotas allow the free space to be used for storage.
