Just the Smart Previews and regular Previews files for a single catalog of mine together take up more than 20GB on my portable drive. Otherwise, they'll use a huge amount of space out of your 20GB limit. Though it will work if you store your catalog in Creative Cloud, that only works if your catalogs are small and you don't use Smart Previews - which means you probably don't sync with the mobile apps and therefore have no reason to subscribe. Its database is based on SQLite, and that's why you still can't put catalogs on network volumes, either for personal or collaborative use. Lightroom remains hampered by its outdated architecture.
