cool . . . mine's been running great for over a year with 5 2tb drives . . . 3tb drives were not even an option when i set up my drobo. I'v got it wired to my pc via the esata . . . I use the drobo for easy access though lightroom. . . sounds like you may have over done it with the 15TB unless you have a need for that much storage, you'll be leaving at least one, and maybe two drives doing nothing . . . the nice thing about drobo is that it's plug and play so you can start with 4 drives, and when you need more space, just add a drive. . . Like i said, 3tb drives were not even available when i got my drobo and now they are the same price as I paid for the 2tb . . . just buy the storage you need and add more later when the drives have more capacity and are cheaper . . . make sure to back up the drobo! I back mine up to external drives . . .