Virtual Copies in Lightroom - disk real estate questions

does anyone know how creating Virtual Copies in Lightroom works with respect to disk space?

I don't think it creates a duplicate of the file itself, but what about adding to database size, or the previews, etc. -- just trying to get a feel for Lightroom and figuring out what gets stored and where, and how the operations I perform affect disk space.

Very little... its only meta-data instructions in the data base.

The previews take up a [I]little[I] space. But remember, it's only building the preview for the size of your screen... it's not building the final full quality image.

1:1 previews make take a bit more space, but LR is usually set by default to discard its 1:1 previews after 30 days, so you actually reclaim disk space if you haven't looked at picture at 1:1 for awhile.

Sorry, I don't have exact numbers for you. Perhaps someone else has heard of actual testing of this?

nah this is cool -- this is what I was looking for -- the meta instructions. I had a hunch this was the case; I think Aperture handles it the same way.

Virtual copies is one of my favorite things about Lightroom. I can do so much more without depleting my HD. Its a wonderful thing.