Having created the farm and installed the first XenApp 6.5 server, we can consider adding our second XenApp server, XA2. When installing XA1 which created the farm, we had no choice about the session controller; we had to assign it, as only session controllers can become data collectors, holding dynamic information or server load and user connectivity. With only one server in the farm XA1 had to be the a session controller and session host. With XA2 we can install with just the session host role. The reality in having only two servers would mean that we would want both servers to be controllers so we would always have a data collect ZDC; even if XA1 was down. For demonstration purposes we will install it as a session host only. In the next lesson and video we will look more at the data collector election process and remove XA2 from the farm and re-add with the session controller role. We will still only have one ZDC as we have just one zone but either XA1 or XA2 could be elected.
By not adding the session controller role we will see that we are not able set set the election preference for XA2 and XA2 does not listen on port *80 for the XML service or port 2513 for the management of the farm; listening only on these Citrix related ports:
- 1494 ICA
- 2512 IMA
- 2598 Session Reliability
Reducing the amount of servers that hold the session controller role optimizes the ZDC election as fewer servers need to participate.