Networks

I am trying to create a VPN between two SonicWALL's for disaster recovery.

I am confused about what type of VPN to create in the SonicWALL. Should I create a Site-to-Site VPN or WAN GroupVPN? What is the difference between the two?

Site A has a 172.16.1.0/24 data network. We want the DR network to have the same subnet. Of course, we couldn't setup the VPN to go from 172.16.1.0 to 172.16.1.0. Which brings me to my next question...

We will have a SAN at both SiteA and SiteB. The SAN's will be directly connected to a SonicWALL interface. This interface needs to travel over the VPN for data duplication between SANs, but I am confused how the VPN needs to be setup.

Could I assign an interface at SiteA with 172.16.249.0/24 and at SiteB 172.16.250.0/24?

I have a diagram that was given to me by the person who started this project that is no longer available. Any help understanding these concepts would be very helpful!

Here is a link to the diagram that was given to me.

http://s315252367.onlinehome.us/DRSolution.pdf