Whenever you’re deploying Windows Server DFS-Namespaces, you will need to figure out how many servers will be required. A single namespace server can typically handle thousands of referrals per second (the exact number will depend on details like the number of targets per link, the server configuration, the network bandwidth). Since DFS-N clients will cache those referrals, you will be hard-pressed to find a scenario where a single dedicated namespace server would become a significant performance bottleneck. However, there’s a lot more to this than raw referral performance, like fault tolerance or site awareness.

Full Article: TechNet Blog