Zones are logical groupings of Citrix servers usually based on geographical location. Servers that are members of the same zone share information through their zone’s data collector (ZDC). The ZDC then shares information with the rest of the ZDCs in the farm. The ZDC’s job is to keep track of the following changes that are reported to it by the servers in its zone:
- Server load: The server load is calculated by each server and reported to that server’s ZDC upon any change in the load.
- Client connections: Any logon, logoff, disconnect, or reconnect of a client to a server is reported by that server to its ZDC.
- Published applications: Information on the usage of published applications is reported to the ZDC by each server;
- Server changes: Changes to the IP address of the server or server shutdowns and startups are reported to the ZDC
- License usage: Real-time license usage is reported to the ZDC.
The ZDC pools together all of this information for the servers in its zone, and immediately reports any changes to the rest of the ZDCs in the server farm. Besides, the ZDC is also responsible for ensuring that all the servers in its zone are still active.
It is therefore evident that the continuous availability and proper functioning of the servers in a zone relies heavily on how well the ZDC discharges its duties. A mal-functioning ZDC can wreak havoc on a Citrix server zone, causing rather alarming issues such as non-availability of the Citrix servers, excessive license usage, overloading, etc. The only means by which such anomalies can be averted is by periodically monitoring the performance of the ZDC. A specialized monitor offered by eG Enterprise helps administrators for continuously monitoring the ZDC and eases their job by alterting them of the abnomalities at the earliest