I have pitched this in other forums.. I HAVE READ the How to Optimize Lightroom performance and acted on every item and then some I have figured out on my own as well as read elsewhere.
Though through all of this one of the things I cannot still do to both better manage diskspace and performance is seperate my Previews.lrdata file from the Catalog.lrcat. My previews, images, program, and catalog themselves are stored off on separate drives.. but the previews file is still full of images and over 60 gigs at the particular moment and I regularly purge it off down to 0.
I would like to be able to put all of these items in separate drive locations if I choose. Today I have items 1-4 in separate locations.
1) Program / OS
2) RAW Images