Hi there,
In my opinion I would certainly say that a server is the best way to record the footage on site. You may hear the term NVR banded about but in almost all cases this is just a standard windows server (occasionally linux) but specified and built by the manufacturer (at a premium naturally) and not all NVR’s accept all cameras so I believe it is safer to opt for a server and an IP software package such as Milestone, Exacq or Mirasys to name a few of the more popular ones, as these will give you a lot more options now and in the future.
There is so much choice on the IP camera front at the moment and to confuse matters further it is not always a case of you get what you pay for. You will probably hear the more common names such as Axis, Sony and Panasonic but Axis are probably the most popular. It is worth bearing in mind that the better Axis cameras do tend to be a bit expensive and in terms of image quality there are actually better cameras for the money. The cheaper axis cameras do tend to perform quite poorly in low light compared to some of the other brands but for internal general use they are pretty good and very reliable and usually come with a good warranty. For external cameras this is more tricky as many cameras suffer from motion blur in dark conditions. There are a few better ones which come in either a vandal dome or bullet style housing with in-built IR lights which are superb up to about 25m and are still POE. We have had great success at a school in North London with these and the customer has been extremely pleased. But on this site we have actually recommended three different manufacturers because every shot has been different and we specified the camera that we knew would suit the environment.
As with all things there are options to suit all budgets and if you were going to try and do it all in house then I would say opting for something like Axis on any of the above platforms would probably be the cheapest and easiest overall.
If you are looking to go down the route of getting an external company in to manage the project and look after the equipment then the added benefit here is that a separate network with any performance issues would be their problem.
After reading a few of the posts above again I think it is worth re-emphasising the issue of processor power as it is important. It is true that lack of processing power is usually the biggest cause of performance issues in our experience. We have a system that is currently running 16 x 1080p (2mp cameras) at 5fps constant recording, 3 x 8mp cameras @ 16 fps each on motion detection and a 5mp external dome at 5fps on motion. We have a server running 2 x Intel Xeon E5-2609 processors, 16GB RAM and RAID5 storage with 12TB available.
Current stats are 24 days storage, even with constant recording on 16 of the cameras and the CPU usage never goes above 30% even at the busiest times. The installed system was designed to take 40 cameras on similar settings and we have 3 spare drive bays for further expansion if needed. We will be moving everything over to motion record in due course. There is a separate network installed and the viewing stations have all had I7 processors installed and the whole system runs like greased lightning. This was overspecced in my opinion but it is what they wanted.
Bandwidth is a concern in certain circumstances but you would struggle to hit anywhere near 600mbps from 30 HD cameras on h.264. 30 x 2mp cameras on 25fps live streaming would be at most around 250mbps to 280mbps. So you can start to see how reducing frame rates to 5fps suddenly makes viewing several streams live at viewing stations less of an issue than it used to be. 30 cameras on 5 fps drops the bandwidth to around 60mbps when viewing live and as long as you have a 1 GB uplink at the key points you shouldn’t experience any issues.
Hope that helps but again if you have any questions feel free to touch base.
Kind regards
Paul