Innocent, that is me! 0:-)
First, the camera system should allow and require a login for the web stream.
Second, are you going to have the video run non-stop, or use motion sensor?
I am working on getting a similar setup here at work, but without the video stream (for now). If the three cameras record everything, I am looking about 4 gigs a day. If motion sensor, about 40 megs.
As soon as I figure out how large of a hard drive the older pc will support, I will be adding a second drive for all of the video to be recorded to.
https://www.techrepublic.com.com/5208-7343-0.html?forumID=101&threadID=307246&messageID=3058871
Of course, the resolution and number of frames per second will effect your file size. All you can really do is turn it on for 24 hours and see what you are looking at.
[i]~he said "booby", hee hee hee![/i]