Circle packing is one of my favorite applications to display hierarchical data where one dimension defines the radius, like the file size. Other dimensions may alter color or line width.
Circle packing is available as an example in D3, highly recommended.
I don't think defining the radius with data makes for good charts, because we tend to perceive the area as size, not radius, and area of course scales with the square of the radius.
So if you have 2 circles depicting files, and one of the files is 3x the size of the other, its circle will have 9x the area and appear 9x larger.
Circle packing is available as an example in D3, highly recommended.
https://observablehq.com/@d3/zoomable-circle-packing