Assess Hardware Requirements
Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2
Review and document the existing hardware configuration of each domain controller that you plan to upgrade to Windows Server 2003. Use this information to identify the domain controllers in your environment that you can upgrade to Windows Server 2003 and the domain controllers that do not meet the hardware requirements necessary to run Windows Server 2003. You can retain domain controllers that do not meet the necessary hardware requirements to serve as rollback servers in the event that you must roll back your deployment. In most cases, a Windows 2000–based domain controller meets the requirements to be upgraded to Windows Server 2003, as long as it has adequate disk space.
At minimum, a domain controller requires available free disk space for the Active Directory database, Active Directory log files, SYSVOL, and the operating system. Use the following guidelines to determine how much disk space to allot for your Active Directory installation:
On the drive that will contain the Active Directory database, NTDS.dit, provide 0.4 gigabytes (GB) of storage for each 1,000 users. For example, for a forest with two domains (domain A, domain B), with 10,000 and 5,000 users respectively, provide a minimum of 4 GB of disk space for each domain controller that hosts domain A and a minimum of 2 GB of disk space for each domain controller that hosts domain B. Available space must equal at least 10 percent of your existing database size, or at least 250 megabytes (MB), whichever is greater.
On the drive containing the Active Directory log files, provide at least 500 MB of available space.
On the drive containing the SYSVOL shared folder, provide at least 500 MB of available space.
On the drive containing the Windows Server 2003 operating system files, to run setup, provide at least 1.25 GB to 2 GB of available space.
For more information about assessing the hardware requirements of domain controllers in a Windows Server 2003 domain, see "Planning Domain Controller Capacity" in this book.