Its really going to depend on what VMS you are using, and how it operates. For example the way that motion detection is processed if your using Server Side or Camera Side VMD, that will step your CPU requirements way up. The number of users, the number of streams each user is watching, there are so many variables that its almost impossible. But generally the manufacturers are going to give you some sort of estimate or recommendations based on their average use, then you take good judgment and common sense and base your system around that. Manufacturers like ONSSI will actually help you spec out the server or give your specs based on your needs, Exacq its really hard to under build one these days because its not resource intensive.
But as for calculators I have not seen anything and having the VMS manufacturer onboard and assisting is the best solution if your not sure.
Like Undisclosed 1 says, it really depends on the VMS. It can't be simplified to a certain number of cameras needing a certain processor/RAM combo.
Moreover, you want the manufacturer to fully support the system, so asking and following their recommendations is important. If you don't follow them, they could simply come back to you should issues arise and tell you the server was under specified.
All that being said, I can sum up some recommendations from our VMS Server Load Fundamentals:
- You're better off spending money on increased CPU than increased RAM. Memory is rarely a limiting factor in throughput handling on a VMS server. If there is a lot of processing happening, like advanced analytics or server side motion detection, it may have an effect, but even this varied depending on the VMS.
- Running server side VMD can max a CPU very quickly. For example, in our tests, server side VMD on 10-12 cameras added 20% or more CPU usage. This is why camera side VMD is as prevalent as it is.
- Finally, unless you're running very low camera counts and relatively low resolution, don't view video on the VMS machine. Viewing only 4-5 1080p cameras can drive a low end PC to 100%.
Thank you all for your ideas.