Checklist: Add a Global Catalog Server
Applies To: Windows Server 2008, Windows Server 2008 R2, Windows Server 2012
If you have more than one domain in your forest and you have a significant user population in a site, you can optimize the speed and efficiency of domain logons and directory searches by adding a global catalog server to the site.
If you have a single-domain forest, global catalog servers are not required for logons, but directory searches are directed to the global catalog. In this case, you can enable the global catalog on all domain controllers for faster directory searches.
(Optional) Review global catalog concepts.
Add or remove the global catalog read-only directory partitions from a domain controller in the site.
Confirm that all read-only directory partitions have been replicated to the new global catalog server.
Verify that the global catalog server is being advertised in Domain Name System (DNS).