Appendix A Hdd Capacity Calculation - Dahua 41HS-W-S2 Series User Manual

8

Appendix A HDD Capacity Calculation

Calculate total capacity needed by each device according to video recording (video recording type and
video file storage time).
Step 1: According to Formula (1) to calculate storage capacity
needed for each hour, unit Mbyte.
Step 2: After video time requirement is confirmed, according to Formula (2) to calculate the storage
m
capacity , which is storage of each channel needed unit Mbyte.
i
Step 3: According to Formula (3) to calculate total capacity (accumulation)
channels in the device during scheduled video recording.
Step 4: According to Formula (4) to calculate total capacity (accumulation)
channels in device during alarm video recording (including motion detection).
q
i
In the formula: means the bit rate, unit Kbit/s
In the formula:
means the recording time for each day (hour)
i
means number of days for which the video shall be kept
i
c
In the formula: means total number of channels in one device
In the formula：a% means alarm occurrence rate
that is the capacity of each channel
   
d 8 3600 1024
i
= × ×
c
T i

i 1
c


q m
×a%
T i

i 1
that is needed for all
q
that is needed for all
T
391
(1)
(2)
(3)
(4)