Mastering Active Directory - Second Edition

Global catalog server placement

Global catalog servers are responsible for keeping a fully writable copy of objects in its own domain and a partial copy of all other domains objects in the forest. It facilitates querying about objects in the entire forest. The global catalog service is part of the domain controller services, and it cannot be separated.

In a single-forest-single-domain environment, all the domain controllers can be global catalog servers as it won't be different from domain replication. But in a multidomain environment, global catalog server placement involves planning as it increases the amount of data to be replicated, as well as the bandwidth.

There are certain things that you need to consider when you're placing a global ...