The XenDesktop 7 Setup docs clearly specifies that Director and other components can be installed on the same machine, but for redundancy and scaling you can split them up as needed. As our environment has 2 delivery
controllers, I wanted to setup a load balancing server, but when I attempted to add the server, I received an error that offered exactly 0 results in a search (that’s never a good sign!). Since I am working on documentation that is due Monday morning I decided to call in a case right away. Citrix returned my call quite promptly (less than 45 min after hours) and the engineer instructed informed me that when the STAs are added they are treated as objects in Netscaler and thus already exist. You can bypass this error by unbinding the STAs, adding the servers, then re-binding the STAs.