Migrating to Windows Server 2008 R2 – Big Bang Migration
The Big Bang to migration from Windows Server 2003/2008 to Windows Server 2008 R2 is the most straightforward of the migration approaches. The upgrade simply takes all the settings on the domain controllers and upgrades them all to Windows Server 2008 R2. If a Windows Server 2008 installation server handles WINS (Windows Internet Naming) service , Dynamic Host Configuration Protocol (DHCP), and domain name system (DNS) the upgrade process will upgrade all the WINS, DHCP, and DNS components, as well as the base OS.
This makes a Big Bang migration very attractive, and it can be extremely effective and efficient. However each of the prerequisites below must be satisfied:
- The OS on the domain controllers must be Windows Server 2003 SP2 or higher.
- The domain controller hardware exceeds the minimum Windows Server 2008 R2 requirements and all the software is compatible with Windows Server 2008 R2 (this also includes drivers and antivirus software).
- There is sufficient available disk space to perform the OS and Active Directory upgrade. Specifically, the available space must be at least twice the size of the Active Directory database plus the minimum 32GB needed to install the Windows Server OS.
- The current domain functional level is Windows Server 2003 or Windows 2000 Native. Upgrade cannot be done directly from Windows 2000 Mixed, Windows NT 4.0, or Windows Server 2003 interim domain functional levels.
Windows Server 2008 R2 Hardware Requirements
Prior to performing an upgrade it is critical to test the hardware compatibility of any server which will be directly upgraded to Windows Server 2008 R2. The server hardware should be verified for Windows Server 2008 R2 on the manufacturer’s website or on Microsoft’s HCL (Hardware Compatibility List) at http://www.microsoft.com/whdc/hcl/default.mspx.
Microsoft suggests the minimum hardware levels for Windows Server 2008 R2, but it is recommended the installation is done on higher spec hardware because the minimum requirements are only for running the base Windows Serve OS and account of application loads, domain controller duties, etc. The below is Microsoft’s minimum hardware specs for Windows Server 2008 R2:
- 1.4GHz 64-bit processor
- 512MB of RAM
- 32GB free disk space
Windows Server Version Upgrade
The version of the OS that which will be upgraded is an important consideration in the upgrade process. Windows Server 2003 SP2 or R2, Standard Edition domain controller can be upgraded to Windows Server 2008 R2 Standard Edition or Windows Server 2008 R2 Enterprise Edition.
A Windows Server 2003 SP2 or R2 Enterprise Edition install can only be upgraded to Windows Server 2008 R2 Enterprise Edition.
Verifying Application Compatibility with Windows Server 2008 R2
It is crucial to identify all apps on a server that will be running in the new environment and verify that each is compatible with Windows Server 2008 R2.
Pre-Migration Back Up and Recovery Process
A good backup and recovery strategy is essential for quick recovery in the event of an upgrade failure. Often, especially with an in-place upgrade, a full system backup may be the only way to recover and consequently, it is very critical to detail fallback steps in the event of problems. The backup should also include the boot and system partitions as well as the System State.
Performing an Upgrade on a Single Domain Controller Server
After application and hardware compatibility has been validated, a standalone server can be upgraded.
Prior to upgrading the domain controllers the Domain Controller Diagnostics (DCDIAG) utility should be
run and any errors fixed prior to the upgrade (the Windows Server 2003 DCDIAG utility is part of the Support Tools, which is located on the installation media at \support\tools\ )
Prior to upgrade the Active Directory Domain Services forest and the domain need to be prepared by installing the schema updates which are new to Windows Server 2008 R2 Active Directory. The below steps should be run on the Flexible Single Master Operations (FSMO) role holder(s), – specifically on the schema master for forestprep and the
infrastructure master for domainprep. For a small environment or single domain, these roles are all typically on the same domain controller. To prepare the forest and domain, execute the following steps on the domain controller with the roles:
- Insert the Windows Server 2008 R2 DVD into the drive – close the autorun page if it appears and then select Start > Run. (When preparing the forest, ensure that you log on to the schema master as a member of the Schema, Enterprise, and Domain Admins group).
- Enter d:\support\adprep\adprep.exe /forestprep and then select OK. (d: is the DVD drive).
- A warning will appear to verify all Windows 2000 domain controllers are at Service Pack 4 or higher. Enter C and hit Enter to commence the forest preparation.
- Enter d:\support\adprep\adprep.exe /domainprep /gpprep and select OK.
- Enter d:\support\adprep\adprep.exe /rodcprep and select OK. This update allows Read-Only Domain Controllers.
Now that the schema updates have been performed and the domain preparation is complete, the domain is ready for upgrade. The first Windows Server 2003/2008 domain controller to be upgraded should be FSMO role holder. Follow the below steps:
- Insert your Windows Server 2008 R2 DVD in the DVD drive.
- The Install Windows page will appear automatically, otherwise select Start > Run and then enter d:\Setup, with d: as the DVD drive.
- Select Install Now.
- Click Go Online to Get the Latest Updates button which will ensure the installation has the latest info for the server upgrade.
- Enter your product key and hit Next.
- Select I Accept the License Terms on the License page, and hit Next.
- Click the Upgrade button.
- Review the compatibility report generated by the wizard and ensure that all issues have been addressed and then click Next.
- The upgrade wizard then copies the required files and reboots as a Windows Server 2008 R2 server and continues the upgrade process. When all files have been copied, the system is then upgraded to a fully functional Windows Server 2008 R2 install and it will then reboot once more.
- After this last reboot, the domain controller will be on the standard Ctrl+Alt+Del screen. After logon, the domain controller opens to the Server Manager console. The domain controller upgrade is now complete.
This upgrade process should then repeated for each of the remaining Windows Server 2003/2008 domain controllers.