I have a gig of nTop RRD files and I would like to start graphing them with rrdtool (but not with nTop, since I'm hoping to do this with a separate backup of the database as workaround to the impossibility of limiting the RRD files by size), but I don't know how the files are structured.

I've tried reading the RRD documentation from SourceForge and the nTop FAQ, but I'm not finding the information I need. Does anyone know of any documentation I should be looking at or how the files are structured?

Here https://dl.dropbox.com/u/669437/file%20structure.png is a screenshot of the file structure. At first I thought it was organized by IP address (so the rrd files for address 1.1.2.3 would be stored in folder 1->1->2->3 or even the reverse order), but that doesn't seem to be the case. It isn't organized by MAC address either, although some hosts are saved that way.

Any help would be appreciated.