Ten-Year Medical Imaging Archive

A group of hospitals produces about 40 TB of X-ray and MRI images a month. Radiologists look at a scan often in its first month, rarely after that, and almost never after a year, but regulations require every image to be kept for ten years, unaltered, and retrievable within twelve hours when a court or a patient asks. Images must be encrypted at rest with keys the hospital group controls, and moving older images to cheaper storage must happen automatically rather than by someone running scripts. The overall storage bill must stay as low as possible.