Javik 0 Posted October 16, 2015 I'm trying to do some math. Do these numbers check out with the rest of you? Example unit: Dahua IPC-HDBW4300E Max resolution: 2052x1536 @ 20FPS Max bitrate: H.264 8192kbps Bitrate in bytes: 8192 kbps / 8 = 1 megabyte/sec Max recording time, 24 hrs a day: 60 sec * 60 min * 24 h = 86400 seconds 86.4 gigabytes per day for 1 camera * 16 cameras = 1.38 TB per day * 32 cameras = 2.76 TB per day recording 24 hrs per day Network bandwidth incoming to stream recorder: 8192 kbps * 16 cameras = 131 megabit 8192 kbps * 32 cameras = 232 megabit =================================== We are a school district. Our main building activity from 8am to 4pm with occasional before/after-school activity from sports and maintenace staff. If we do motion detection in the capture server, we can probably reduce daily recording to maybe 8 hrs or 6 hrs per camera. There is minimal activity on Saturday/Sunday, so for us a "week of data" is 5 days. 4 weeks of recording time: 20 days ==================================== 8 hrs per camera per day, 16 cameras: 60 s * 60 m * 8 h = 28800 seconds 28.8 gigabytes per camera * 16 cameras = 460.8 gigabytes per day 4 weeks of recording time: 460.8 * 20 days = 9.2 TB 32 cameras: 18.4 TB ==================================== 6 hrs per camera per day, 16 cameras: 60 s * 60 m * 6 h = 21600 seconds 21.6 gigabytes per camera * 16 cameras = 345.6 gigabytes per day 4 weeks of recording time: 345.6 * 20 days = 6.9 TB 32 cameras: 13.8 TB ==================================== Western Digital RED, 6 TB for $250, 3 yr warranty Western Digital RED PRO, 6 TB for $320, 5 yr warranty RAID 6 = 2 redundant parity drives + spanned data drives + optional hotspare drives 6 TB * 2 data = 12 TB + 2 parity + 1 hotspare = 5 drives Qty 5 WD RED, 6 TB = $1250 Qty 5 WD RED PRO, 6 TB = $1600 6 TB * 3 data = 18 TB + 2 parity + 1 hotspare = 6 drives Qty 6 WD RED, 6 TB = $1500 Qty 6 WD RED PRO, 6 TB = $1920 6 TB * 4 data = 24 TB + 2 parity + 1 hotspare = 7 drives Qty 7 WD RED, 6 TB = $1750 Qty 7 WD RED PRO, 6 TB = $2240 6 TB * 5 data = 30 TB + 2 parity + 1 hotspare = 8 drives Qty 8 WD RED, 6 TB = $2000 Qty 8 WD RED PRO, 6 TB = $2560 * Cost not including the server itself with CPU, memory, OS, capture software, etc Share this post Link to post Share on other sites
ak357 0 Posted October 16, 2015 I'm trying to do some math. Do these numbers check out with the rest of you? Example unit: Dahua IPC-HDBW4300E Max resolution: 2052x1536 @ 20FPS Max bitrate: H.264 8192kbps Bitrate in bytes: 8192 kbps / 8 = 1 megabyte/sec Max recording time, 24 hrs a day: 60 sec * 60 min * 24 h = 86400 seconds 86.4 gigabytes per day for 1 camera * 16 cameras = 1.38 TB per day * 32 cameras = 2.76 TB per day recording 24 hrs per day Network bandwidth incoming to stream recorder: 8192 kbps * 16 cameras = 131 megabit 8192 kbps * 32 cameras = 232 megabit =================================== We are a school district. Our main building activity from 8am to 4pm with occasional before/after-school activity from sports and maintenace staff. If we do motion detection in the capture server, we can probably reduce daily recording to maybe 8 hrs or 6 hrs per camera. There is minimal activity on Saturday/Sunday, so for us a "week of data" is 5 days. 4 weeks of recording time: 20 days ==================================== 8 hrs per camera per day, 16 cameras: 60 s * 60 m * 8 h = 28800 seconds 28.8 gigabytes per camera * 16 cameras = 460.8 gigabytes per day 4 weeks of recording time: 460.8 * 20 days = 9.2 TB 32 cameras: 18.4 TB ==================================== 6 hrs per camera per day, 16 cameras: 60 s * 60 m * 6 h = 21600 seconds 21.6 gigabytes per camera * 16 cameras = 345.6 gigabytes per day 4 weeks of recording time: 345.6 * 20 days = 6.9 TB 32 cameras: 13.8 TB ==================================== Western Digital RED, 6 TB for $250, 3 yr warranty Western Digital RED PRO, 6 TB for $320, 5 yr warranty RAID 6 = 2 redundant parity drives + spanned data drives + optional hotspare drives 6 TB * 2 data = 12 TB + 2 parity + 1 hotspare = 5 drives Qty 5 WD RED, 6 TB = $1250 Qty 5 WD RED PRO, 6 TB = $1600 6 TB * 3 data = 18 TB + 2 parity + 1 hotspare = 6 drives Qty 6 WD RED, 6 TB = $1500 Qty 6 WD RED PRO, 6 TB = $1920 6 TB * 4 data = 24 TB + 2 parity + 1 hotspare = 7 drives Qty 7 WD RED, 6 TB = $1750 Qty 7 WD RED PRO, 6 TB = $2240 6 TB * 5 data = 30 TB + 2 parity + 1 hotspare = 8 drives Qty 8 WD RED, 6 TB = $2000 Qty 8 WD RED PRO, 6 TB = $2560 * Cost not including the server itself with CPU, memory, OS, capture software, etc 1.drop down bitrate to 4096 kbps 2.set unit to VBR Not CBR You will save some recording space Share this post Link to post Share on other sites
ilk 0 Posted October 20, 2015 Consider using WD Purple NV disks for NVR applications WD Red HDDs are designed for NAS applications Ilkie Share this post Link to post Share on other sites
survtech 0 Posted October 27, 2015 I would do the calculations slightly differently. Assuming you use 8Mbps (and you will have to decide that by trial and error to select the minimum bit rate that provides acceptable images), 8x60x60x24=691200/8=86400/1024=84.375GB per day. Remember a gigabit is 1024 bits and a terabit is 1024 gigabits (the same applies to bytes). CBR data requirements are the easiest to calculate while VBR can be very complex. The actual disk space used can vary quite a bit depending on the camera design, codec used and amount of motion in the video (including noise in low light situations). There are also differences in how manufacturers treat VBR. Some use a hard cap at the specified setting so the bit rate will never exceed what you specify but will float down when little is happening, whereas others let the bit rate float both below and above any setting. With the latter, bit rates can actually run incredibly high during motion or when the video is noisy. Remember when using RAID6, two drives worth of data are parity drives and they can't be included in storage calculations. Example - a 12-bay chassis running RAID6 with 3TB drives would yield 36TB raw but the net would be around 30TB (slightly less with Windows overhead). Another thing to keep in mind is drive error rates. Typical specs call for one unrecoverable error in 10 to the 15th bits (1petabit). I tend to think that is way over-optimistic. Also, as RAID Group size gets larger, so do rebuild times. In fact, a 12-disk RAID6 group takes at least 48 hours to rebuild with most storage systems. During that time, the system is running in "degraded mode", which limits data throughput and also increases the system's vulnerability to faults. For those reasons, I refuse to utilize RAID groups larger than 12 drives and with larger than 3TB disks, would actually seriously consider smaller (<=8-disk) groups. Of course, the problem there is the point of diminishing returns. A 12-disk group of 3TB disks would have a bit under 30TB of usable space with 6TB, or 1/6 of the total, dedicated to parity. An 8-disk group of 5TB disks would also have 30TB of usable space with 1/4 of the total dedicated to parity. The larger the drives, the worse it gets. 8TB disks in a 6-disk group yields 32TB usable but sacrifices 1/3 of the drives to parity, Etc., etc... You have to decide how long rebuild times you can accept. If a 36TB raw (30TB net) group takes 48 hours to rebuild after a HDD failure, a 72TB raw group would take over 4 days. And you must assume disks WILL fail. Not if, but when... Share this post Link to post Share on other sites
