Subscriber Discussion

Using Multiple NVRs For High Camera Count Installations

This is kind of a basic question but I am asking about installations of high camera count (300+ for example). I know that there are usually a handful of VMSes that support "unlimited" camera counts to choose from.

I find however that a lot of integrators claim that they simply purchase multiple NVRs and somehow link them together. Is this possible? will this approach have any drawback or feature limitations?

I hope my questions isn't unclear or really basic.


Most VMSes should be able to let you work with "unlimited" cameras... however, when it comes to the NVR itself, regardless of what the software allows, you'll still run into limits on what the hardware can handle - there will be a bottleneck somewhere, be it network bandwidth, CPU, disk I/O, etc. With 300+ cameras, you're definitely looking at multiple recorders.

I've worked mainly with two systems: Vigil and Dahua. With both, the recorders support up to a max of 32 cameras, but the client/VMS can be configured with multiple servers/ DVRs/ NVRs, with no set limits on how many, and display, search, and playback any combination of cameras from different recorders (Dahua's VMS can also directly access their cameras and playback internally-recorded video). There's theoretically no limit on how many cameras either system will support, although you may find there are limits to how many a person can PRACTICALLY manage in one interface.

The key issue is what administrative functionalities the VMS/NVR builds in:

  • Do they support a single sign on to access all boxes or do you need to create and maintain a separate user account for every physical machine?
  • Can you pull up cameras from different boxes on the same client? This is increasingly common but not universal.
  • How can you manage cameras across boxes? Do you need to connect to each one separately to change settings/configuration or are all cameras available on a single UI/screen to simplify mass administrative changes?

It's certainly possible but one needs to check with their preferred VMSes to see (1) whether or not they have these functionalities? and (2) what license level you need to access them?

Thanks guys, things are getting clearer now. Do NVR vendors clearly state if they support these administrative functionalities? If they do not mention anything about the issue, could i safely assume that they don't support them?

No, you have to ask specifically. I would simply forward my three questions to any vendor you are interested.

Marketing material is especially vague on this functionality, especially since it can be open to interpretation what 'enterprise' really means.


There are a lot more than "a handful" of VMS's that support 300 or more cameras through multiple networked NVRs. Just the list we looked at (some of which we evaluated) would fill up two hands: Avigilon, Milestone, ONSSI, DVTel, Geutebruck, NiceVision, Honewell Enterprise, Synectics, Genetec, IndigoVision, Surveillus and, I believe, Exacq, among others.

^Vigil and Dahua too :D

Do NVR vendors clearly state if they support these administrative functionalities?

Marketing types rarely "clearly state" anything.

Also, depending on the target market specific advertising is aimed it, it may focus on certain features and ignore others. As John says, it's always best to ask if you're looking for a SPECIFIC feature. As John also indicates, if they do claim to support it, it's probably best to get a demo of the feature before committing to a platform - just because a system supports a feature, doesn't mean it supports it well, or to the degree you need.

If they do not mention anything about the issue, could i safely assume that they don't support them?

Do you know what the basic makeup of human life is? DNA - Do Not Assume.

The other aspect we did not talk about is performance. At 300 cameras, you probably won't see major performance issues but with thousands of cameras you often see that. There can be significant delays in logging in or pulling up cameras or making changes, etc.

This is hard to verify outside of asking for similar sized references and hoping those references are honest / now what they are doing.