Hard disk capacity required for hard disk video recorder = 225× 8×12×15 = 324,000 MB ≈ 320 GB 8-channel CIF format. How much capacity do you need for 24-hour uninterrupted video recording for 30 days?
8-way×× 200m× 24 hours× 30 days ÷1024m =1125g (note: 1G = 1024M).