70-294 Concepts: Where to place Global Catalogs

When designing a multi-site environment, here are the considerations you should take when deciding which sites require a Global Catalog:

  • Use a Global Catalog instead of Universal Group Membership when AD information is required by an application at another site
  • Uses more bandwidth compared to Universal Group Memberships
  • Requires greater computer resources compared to Universal Group Memberships
  • When you want to control Global Catalog replication, use the Preferred Bridgehead Server setting
  • IgnoreGCFailures registry key; apply to all DC to prevent GC failures from preventing logon