Dual Datacenter Business Continuity Configuration

Hi All,

I'm working on a business continuity project.

My goal is to have a 2nd datacenter where I replicate the Virtual Machines.

I'm trying to find the best solution for the network.

AS IS:

Right now all the buildings and department are connected to the HQ1.

The datacenter is in HQ1.

DPT-1 is phisically located next to HQ1.

DPT-2 is phisically located next to HQ2.

Building-3 is phisically separated from HQ1 and HQ1.

All the routing is done by Fortigate cluster in HQ1

HQ2 at the moment has only a switch that connect that part of the network to HQ1 where the datacenter is located. The link is with a single private fiber link that pass under a street.

All the vlan are spreaded across the network and divided by function not by department (es client vlan, server vlan etc)

TO BE:

I have to avoid interruption caused by fiber issues.

We'll replace the current fortigates in HQ-1 with a cluster of 121G.

We'll add a cluster of 121G in HQ2.

We'll add a new ISP link in HQ2.

We can add radio link for fiber redundancy (link in blue color in the diagram)

Now the question is: Is it better to have a single cluster of 4 fortigates or is it better to split it into 2 clusters and manage HQ1 as a standalone network with his vlans and the same for HQ2?

If the second solution is better how can i manage BUILDING-3 network redundancy?

I attach the solution 1 and solution 2 diagrams

Thanks.

Regards.

solution 1

solution 2