I'm a big fan of DrivePool (by StableBit) for Windows. You can add as many hard drives as you want and pool them together into one, optionally add duplication,

I'm a big fan of DrivePool (by StableBit) for Windows. You can add as many hard drives as you want and pool them together into one, optionally add duplication, and if anything fails, each hard drive is just an NTFS volume that can be accessed with any other computer. https://stablebit.com/ https://stablebit.com/