As CitectSCADA supports clustering and the ability to run multiple servers of the same type on one machine, there are circumstances when the server component parameters (Alarm, Report, Trend, IOServer) need to be tuned to a finer level than just machine level. For this reason, these parameters are hierarchical parameters that are capable of being implemented at a number of levels:
The widest scope, the parameter value will apply to every instance of the server type.
The parameter value will apply to every instance of the server running in the specified cluster.
The parameter value will apply to the instance of the server running in the specified cluster, on the specified machine.
These parameters support hierarchical inheritance, that is, a parameter will:
Example
The following Citect.ini
file
is applied to Server1 and Server2 both in Cluster1, and
to Server3 and Server4 both in Cluster2.
[Alarm]SavePeriod = 500
[Alarm.Cluster1]SavePeriod = 600
[Alarm.Cluster1.Server1]SavePeriod = 1000
This is illustrated in the diagram below.
The values applied at each server for [Alarm]SavePeriod would be as follows:
Cluster Name |
Computer Name |
SavePeriod Value |
---|---|---|
Cluster1 |
Server1 |
1000 |
Cluster1 |
Server2 |
600 |
Cluster2 |
Server3 |
500 |
Cluster2 |
Server4 |
500 |
Note: Hierarchical parameters may be set in the parameters database. In this case normal rules of precedence will apply. For more information see Parameter Precedence.