You have many options . All of them have different costs associated with them . It really depends on how old and large the hard drives you have currently are and what your data storage needs are . Move your data to larger hard drives . If you are running 4 x 2 TB drives , then you can easily swap them out with 2 x 6 TB drives and leave room for the future . Purchase external storage if you have USB ports available . You can get anything on the order of 8 TB redundant or less . Move your computer components into another case which will fit plus all of your existing hard drives and future hard drives . If you intend to add hard drives , you ' ll need to have either SATA ports available or a PCIExpress bus available to put a SATA expansion card in . or there are a few more hacky options but none easier than a new motherboard . Purchase a new computer for storage purposes and attach it to your network . If your hard drives are in the 12 TB range I would recommend purchasing 4 TB drives to install in the existing space and move the data over . I would recommend mirrors either 2 x RAID 1 or 2 x ZFS mirrors as that will give you redundancy and also future expansion with only 2 drives changed out . If your hard drives are already in the 34 TB range I would recommend purchasing a case with 8 or so hard drive bays and a PCIExpress SATA expansion card . Fractal Design R 5 , for example . excellent case sub $ 100 with plenty of drive bays . Then , move your entire setup into the new case and add your drives as desired . If you are already running large hard drives 610 TB and filling them up quickly , then you should invest in constructing a dedicated NAS computer . A motherboard with lots of SATA ports and a case with 820 drive bays depending on your future needs .