Been there, done that. Sold my NAS after the experiment. The NAS that will fulfil my needs are way out of my budget. Even the WD Sentinal & Seagate BlackArmor (Limited to their own limited Hard Drives and excruciatingly slow recovery in RAID 5) won't do. So have to go this way instead . Ideally I'd prefer to have 20TB available space after RAID 10, upgradeable to atleast twice that. My solution is 2 * PCs, each with 17tb (5 * 3tb + 1 * 2tb).