Readynas 428 and onvif camera

I use and am very happy with Blue Iris -- https://blueirissoftware.com.  It is very full featured and quite reasonably priced.  I'm still using V4, but expect to upgrade soon.  I sent a thief to prison for 39 months based on my footage.  I just had to give a copy to his lawyer, and he wanted to plea bargain.

I used to use an older Core2 Quad computer with Win10 and 1TB of internal storage with the NAS as the backup storage location (using the built-in backup, not a separate backup program).  I would still be using that computer except that it failed and instead of trying to replace it, I got a rack-mount dual hexa-core Xeon computer that is way overkill for just surveillance and also use it for other applications.  I have 5 ONVIF cameras of various makes and even used the webcam of a laptop as a camera (and got a great video of the guy about to steal it).

I personally don't see the advantage of running a surveillance program on a headless NAS when a PC with a monitor is far better for it and there are so many options there.

Not many cameras still have FTP capability, but that used to be another way to utilize a NAS for surveillance storage.