Q-See QSD2308L User Manual page 75

QSD2308L/QSD2316L DVR User's Manual
For example, if a customer uses NTSC cameras, sets resolution to CIF,
video quality to Lower, frame rate to 240fps for 16ch total, and he wants
the unit to continuously record for a month, below is the calculation:
Storage used in a day: 112.5X24(h)X(240fps/30fps)≈21GB
Storage used in 30 days: 21X30≈630GB
So the customer must install SATA HDDs with 630GB capacity for it to
record a month.
Medium 384
Lower 256
Lowest 128
168.7
112.5
56
71