I am uploading a file geodatabase to ArcGIS Online that is 40MB when unzipped. The resulting feature layer is 170MB. Why is the feature layer so much bigger than the source data? I don't remember running into this in the past. Has there been a change in the last few months?
It appears that the line geometries are taking up about 4.5 times as much space as an AGOL feature layer than as a file geodatabase or shapefile.