Often used for large applications where multiple user groups need to see specific parts of a central application.
For example, based on their security account, a water plant user will only see water (realm) system data and displays, but ‘super user’ logins may be configured to show both water (realm) and wastewater (realm) data and to run system-wide reports.
This approach is used to minimize investment in computer infrastructure without losing historical data backup and automatic server failover capabilities.
Centralized configuration also allows both systems (realms) to be configured from the same computer.