ArcGIS GeoEvent Server
ArcGIS GeoEvent Server is a server licensing role of the ArcGIS Server component in ArcGIS Enterprise. GeoEvent Server can be deployed alongside other ArcGIS Enterprise components, server licensing roles, and feature capabilities. An ArcGIS Enterprise license is required to obtain a GeoEvent Server license. ArcGIS GeoEvent Server leverages component functionality from ArcGIS Enterprise while at the same time enabling real-time capabilities for ArcGIS Enterprise. ArcGIS GeoEvent Server relies on the ArcGIS Server component framework - ArcGIS Server must be installed on a machine before ArcGIS GeoEvent Server can be installed.
It is expected that each machine with ArcGIS Server installed will be licensed for a single server role. It is possible to license an ArcGIS Server machine for multiple server roles, for example, as both a GIS Server and a GeoEvent Server. Doing so, however, runs counter to the best practices for workload separation described in the Esri white paper, Architecting the ArcGIS Platform: Best Practices.
Spatiotemporal big data store
The spatiotemporal big data store is a data store type available in ArcGIS Data Store. When installing or configuring ArcGIS Data Store, you have the option to enable the spatiotemporal big data store. The spatiotemporal big data store should be enabled on a separate machine. For example, a typical deployment would be to install the components of ArcGIS Enterprise (Portal for ArcGIS, ArcGIS Server, and ArcGIS Data Store) on one machine. ArcGIS Server would be licensed as a GIS Server and Data Store configured to provide a relational database ArcGIS Server uses as its managed geodatabase while fulfilling the role of a hosting server for the ArcGIS Enterprise portal.
On a second machine, typically, you would install ArcGIS Data Store and configure the spatiotemporal big data store. Part of configuring the spatiotemporal big data store is registering it with the ArcGIS Enterprise portal's hosting server.
On a third machine, you could install ArcGIS Server, licensing the deployment with an ArcGIS GeoEvent Server license, and then install GeoEvent Server (licensing the second installation with the same GeoEvent Server license). This limits the ArcGIS Server role to support ArcGIS GeoEvent Server, leaving open the possibility the server could be federated with the ArcGIS Enterprise portal.