The company is implementing XenDesktop globally for desktop virtualization. Why should an architect recommend multiple controllers in each datacenter?

Protection against controller database failure is primarily achieved through high availability configurations of the SQL Server database itself, such as AlwaysOn Availability Groups, not by deploying multiple Delivery Controllers.

Users maintain uninterrupted connections to *existing* desktops mainly through features like Citrix Session Reliability or Auto-Reconnect, which handle network interruptions after a session is established, independent of Delivery Controller availability for new sessions.

Protecting users from WAN link failure between datacenters is addressed by having separate, independent XenDesktop sites or resources in each datacenter, not solely by deploying multiple controllers within a single datacenter.

Multiple Delivery Controllers (DDCs) in a datacenter ensure high availability for the brokering service, which is critical for initiating new desktop and application sessions. If one DDC fails, the remaining controllers can continue to process connection requests from users, ensuring that new sessions can still be launched without interruption.