When a Pro user loads a feature class into ArcGIS Enterprise as a hosted feature layer, where is the bulk of the data actually stored? In my example I am using the option "Copy all data" and using the Feature Layer type.
It was my impression that the data would reside in the relational data store. However, when I test this on my sandbox ArcGIS Enterprise deployment, I see very large .sd files created under the Portal install folder at C:\arcgis\arcgisportal\content\items. Is this .sd file the source that is actually read when users view data on a map? And if so, then what is being stored in the data store?