Xenapp 5 Data Collectors

Configuring the Data Collector Service

The data collector service is the hub of a citrix farm, the data collector responsibilities include but are not limited to:-

Information on published applications
Connected Users
Sessions
Licencing
Server Load
Distribution of the above Information to other data collectors in the farm.

Data collectors operate within “ZONES” inside a farm. Zones are groups of servers that are usually grouped by geographical boundaries. Zones are created to minimise WAN traffic. If for example we had offices in Iceland and one in australia, each would have a seperate zone so that users in iceland connect and lanuch published applications from the iceland zone. This would stop them connecting to the australia zone and incuring WAN costs.

In the above configuration you would still get WAN traffic however it would be minimal as only the datacollectors would be relaying information on their status to each other.

Another interesting thing about data collectors is the “election” process. This is the automated process where a data collector is elected as the primary collector and others as backups. This process is completely automated and can be explained in the following.

You have 2 zones (Iceland and Australia) each has 5 servers within their own zone (so the farm has 10 servers in total) . If all servers allowed their data collectors to chat across the WAN it would increase the amount of WAN traffic and potentially cause confusion. So within each zone the election process takes place. This allows one server to communicate the zones status/info etc to the other zome. However also elected are backup data collectors. This will then become the primary data collector should anything happen to the original primary data collector.

Although this is completely automated there are configuration settings you can change to assist the choice of the primary data collector.

MOST PREFFERED
The first choice for the data collector only assign this to ONE server in each zone. For information this is normally automatically assigned to the first xenapp server installed in a zone.

PREFERRED
The second choice for a data collector, more than one PREFFERED data collector can exist.

DEFAULT PREFERENCE
Default settings for servers, if no settings have been manually chosen for the servers then they go into this level of preference. Also in the event of a MP server failure and no manual preference settings have been configured then elections will occur at this level (simply because the PREFERRED option for a server must be manually chosen.

NOT PREFFERED
This is the runt setting for the servers. Servers in this level will only become data collectors if no others are available.

If you leave all the preference settings alone and let the farm get on with it by itself then when we installed the servers in the iceland zone the first server to come online will automatically be designated the MOST PREFFERED server, the other 4 will get the DEFAULT PREFERENCE.