On which managed hosts is QRadar event data stored in the Ariel database?

QRadar event data is stored in the Ariel database on the Event Processor and any attached Data Nodes. The Event Processor is responsible for processing incoming events, performing correlation, and storing the event data. The attached Data Nodes provide additional storage capacity and can be used to extend the storage available to the Event Processor.

ReferencesIBM QRadar SIEM V7.5 Administration documentation.