This is the real rub. As soon as remote storage is a requirement, you start to need some kind of service provider to do it. This service provider could be anything from a purpose-built service to a generic storage service (think S3, Google Drive, DropBox, etc), to a co-located server, to a VPS, to a machine sitting at a friend's house.
No system will be perfect though. What if the internet connection goes down? What if the power goes out? What if the provider for the remote storage goes down?
The amount of storage depends on the camera's resolution and frame rate.
One of my cameras records 640x480 at 1 fps, saving movies at 7 fps when motion is detected. I end up using 1GB to 1.5GB per camera per day, depending on how much motion is being detected. The files saved are 7 fps videos for each event, 1 fps videos for each hour (24 videos), plus the event videos all stitched into one video.
For my purposes, this is sufficient. Other folks might want 720p or 1080p video, have more cameras, etc, and have correspondingly larger storage requirements.
What kind of retention do you implement considering those storage requirements? I mean, a simple 4 camera setup would be 4-6GB/day which is ~1.5-2.2TB/year.
Locally doesn't mean it has to be stored on the same physical premise thus physical access to cameras does not necessarily mean physical access to storage machines/devices. Great work GP, congrats for taking extra steps.
Is there any open-source/documentation that is accessible to more people (not just network experts) on how to do this kind of setup?
There are really three separate problems that need to be solved:
* Remote access to your home network
* Recording and storage of video, possibly with motion detection and alerting.
* Remote storage of video/events (optional).
Each problem is "sort of" solved:
Most routers have some kind of VPN server built in. My Asus router supports PPTP, which isn't very secure, out of the box. I think some routers are starting to support OpenVPN, but without some easy wizard to set it up and distribute the profiles and certificates it would probably be beyond the average user.
A lot of NAS devices come with software to record from IP cameras. My QNAP has it, but I have no idea how good it is as I've never tried it. I know that to use more than two cameras they want you to buy extra licenses.
A lot of NAS devices can also sync folders up to various cloud storage providers. This could solve the optional remote storage requirement.
As for making it all work together, that's another story. I'm not aware of any kind of easy to follow HOWTO for a user who's goal is "access my cameras remotely without sending everything to the cloud".
The ubiquiti unifi video server (formerly aircam?) is ridiculously easy to set up on a local x86-64 linux system. They give away the software free for use with their IP cameras. Or it need not be physically local, the server could be on the other end of a VPN tunnel from the layer2 LAN that physically contains multiple security cameras.
