I shoot architecture and real estate. I'm shooting hundreds of frames daily and my current catalog is getting huge. I'm also starting to see a massive performance hit recently. Last night I was editing until 3:30am because LR would take sometime as long as 20 seconds to perform a single task (like change a slide or flag a photo). Lots of spinning beach ball time. I have an external hard drive that I back up to locally.
What I'm wondering is if I copy everything but the most recent project folders to the external drive then keep that unplugged when I'm editing current work if that would help the performance issues?
Running MacBook Pro (10.9.5) and LR CC. I've optimized my catalog and I've also run Cocktail for Mac on my system to clean out memory, etc.
Any other ideas of managing huge catalogs would be helpful. I'd prefer not to have a new catalog for each client as I shoot for several every day and switching back and forth between catalog daily would be a pain in the butt.
Have you tried increasing/Purging your Cache ? See How to improve and speed up Photoshop Lightroom performance for more ways to optimize Lightroom.
Also what size is your catalog right now?