Rules of Clustering

Using CitectSCADA > Implementing Clustering > Rules of Clustering

Rules of Clustering

When configuring CitectSCADA the following clustering rules apply:

Each cluster to have a unique name.
Each server component to have a unique name.
Each server component needs to belong to one cluster.
Each cluster can contain only one pair of redundant Alarm Servers. They need to reside on different machines.
Each cluster can contain only one pair of redundant Reports Servers. They need to reside on different machines.
Each cluster can contain only one pair of redundant Trends Servers. They need to reside on different machines.
Each cluster can contain an unlimited number of I/O Servers.

There are countless variations in how a clustered system can be configured. The most appropriate configuration will depend on the requirements for the solution to be deployed and the environment in which it is being deployed. For more information, refer to Typical system scenarios.

The diagram below is an example of a system running with two clusters across three machines. Every server and client component have been deployed in accordance with the clustering rules.

The next diagram demonstrates circumstances which do not correctly follow the clustering rules.

The CitectSCADA compiler or the CitectSCADA Runtime Manager detects when the rules of clustering are not being observed and advises the user accordingly.