Chances are that if you still haven’t got around to migrating from Windows Server 2003 to Windows Server 2012 R2, that the OU structure at your organization is pretty much the same as it was when you initially deployed Windows Server.
As mentioned in other posts, migrating gives you a chance to do spring cleaning. You can clear out derelict accounts, clean up data that is no longer being accessed, and reorganize your OU structure.
When many organizations first deployed Active Directory, they based their organizational unit structure on the structure of their organization as it existed at the time. That is, rather than represent the technical needs of the organization in terms of applying group policy or delegating control, it was a straight mapping to how things looked on the org chart. Whether how things looked on the org chart mapped to how things needed to be done technically wasn’t something that people worried all that much about.
Today, which for most organizations is more than a decade since the OU structure was put in place, it’s likely that the OU structure doesn’t meet the technical needs of the organization, but that through more than a decade of organizational restructuring, the OU structure also doesn’t represent the org chart either. Departments will have been merged, split, spun off, spun out, spun back and created. While at some point there was likely to be an attempt by the AD administrators to keep up, if your organization’s still on Server 2003, there’s a good chance that there are OUs in your AD infrastructure for departments that no longer exist.
In the next post we’ll look at Group Policy rationalization, which is something that goes hand-in-hand with OU reorganization.