Multiple disk, splitting cameras across them in groups?

[rorton]

Been doing some reading and some people suggest that if you have multiple disks in your NVR and a larger number of cameras, you would be better off setting up one disk per group, and then assigning the cameras to these groups manually.

Anyone any thoughts on this? The WD Purples seem to suggest that they can handle 64 streams. Looking at the bandwidth used on the NVR interface for all cams recording, mine is at 75Mbps

SATA transfer rate is 6Gb/s, and the quoted host to/from drive (sustained) is 150MB/s (thats for a 4TB purple, the smallest disk I have, bigger disks seem to be slightly more)

150MB/s is 1258Mbps so should be no problem at all?

 

[JB1970]

Been doing some reading and some people suggest that if you have multiple disks in your NVR and a larger number of cameras, you would be better off setting up one disk per group, and then assigning the cameras to these groups manually.

Anyone any thoughts on this? The WD Purples seem to suggest that they can handle 64 streams. Looking at the bandwidth used on the NVR interface for all cams recording, mine is at 75Mbps

SATA transfer rate is 6Gb/s, and the quoted host to/from drive (sustained) is 150MB/s (thats for a 4TB purple, the smallest disk I have, bigger disks seem to be slightly more)

150MB/s is 1258Mbps so should be no problem at all?

The only time I've used that feature is when I had some issues with a particular model of 8MP camera. I used it to put the 2 problem cameras onto their own disk to see if it was a transfer issue (it wasn't). I could see it being advantageous if you had some specific channels that you wanted to prioritise and reserve storage space for so that the video was retained for longer.

 

[rorton]

Thanks, seems it should be more than enough - definitely a great idea there to move a camera to its own disk to rule that out! I'll stick to one group with all the disks in.

 

[JB1970]

Thanks, seems it should be more than enough - definitely a great idea there to move a camera to its own disk to rule that out! I'll stick to one group with all the disks in.

I have 10TB and 4TB Seagate Skyhawk in my 16 channel M2 (the 10TB is one of the AI models). 9 cameras all running at 25FPS, 5 of them are 8MP with bit rate at 16,384 and the rest are 4MP at 8,192 or higher with no issues.

 

[rorton]

I have 10TB and 4TB Seagate Skyhawk in my 16 channel M2 (the 10TB is one of the AI models). 9 cameras all running at 25FPS, 5 of them are 8MP with bit rate at 16,384 and the rest are 4MP at 8,192 or higher with no issues.

how many days recording do you get then with that?

 

[JB1970]

how many days recording do you get then with that?

16 days currently.

 

[rorton]

I was obsessing about the Hikvision bit rate calculator. This system I have all cams running 12fps (26 of them) with 4TB, and 2 x 3TB Purples so 10TB in total, I stuck to recommended bit rates as such, an 8pm ColorVu I have set at 12 fps, variable, and max bit rate of 4096, which is what the calc recommended.

Calc recommends for 8mp at 25fps 8192 bit rate, and you've doubled with yours - are you running quality higher/highest? Do you have a rule of thumb you use for the bitrates?

I got a 10TB WD Pro (the AI one) coming today, so system should have 20TB in total when installed

 

[JB1970]

I was obsessing about the Hikvision bit rate calculator. This system I have all cams running 12fps (26 of them) with 4TB, and 2 x 3TB Purples so 10TB in total, I stuck to recommended bit rates as such, an 8pm ColorVu I have set at 12 fps, variable, and max bit rate of 4096, which is what the calc recommended.

Calc recommends for 8mp at 25fps 8192 bit rate, and you've doubled with yours - are you running quality higher/highest? Do you have a rule of thumb you use for the bitrates?

I got a 10TB WD Pro (the AI one) coming today, so system should have 20TB in total when installed

I wouldn't obsess too much with bit rates, thought too high is better than too low (which will cause issues). I tend to use the storage calculator as a tool for guesstimating how long footage will be retained for when quoting. With VBR, apart from just the frame rate and resolution; the bit rate is going to vary according to how much movement there is in the scene, how frequent that movement is, how much noise there is in the image.

The higher you set the quality setting on the camera, the more the bit rate used will burst above what you've set the maximum to, so I don't use 'Highest' (mine are set to 'Higher'). When setting the cameras I use a recommended bit rate chart which gives figures for various resolutions and bit rates. However as mentioned above, that is taking into account an 'average' scene (whatever that is) and 'medium' quality, so I'll add a percentage to that. As you say for H265 the chart quotes 8192 for 4K 25 FPS and states the figure is for an average scene and to add 20 - 30% to that for a more complex scene. Perhaps 12,288 might be more appropriate for a complex scene AND lower compression.

When I got the M series it was because of the improvements in incoming bandwidth and overall performance over the outgoing I series. The I series UI had become a little laggy as I added higher resolution cameras and I'd had some capture/playback issues with skipped frames. As a test I set everything to run flat out, just to see whether I'd have issues and surprisingly I didn't.

 

[rorton]

Thanks. My disk turned up today and is faulty, grrr, so when that gets replaced I may spend some time increasing quality and bit rates.
I’ve found that using iVMS4200 to do a still capture of the images useful, as it captures at full resolution of the camera, but not sure how good that would be do do a comparison between settings, then take pictures for each setting and see much difference.