I find Lightroom to be excruciatingly slow for this purpose, especially if you have thousands of large files in your archive like I do. Lightroom and aperture are really raw editing programs, and that's what they do best. I prefer a dedicated database, and I have been using Microsoft Expression Media (formerly iView Mediapro, now sold by Phase One under yet another name) for many years. It is fast even with the thousands of images in the database. It lets me put my images on any disk I want, even external drives, and it builds a database without altering or moving the image files, and it lets you find the original file with a click of the mouse.