HA between 3 sites (quizz)

Hi,

Need to resolve this quizz.

Have 3 sites. All of them have fiber optic.

Site 1 has:

Servers, computers, 2 firewalls in HA, every firewall with 2 fiber optic sfps.

Site 2 has

Servers, computers, 2 firewalls in HA, every firewall with 2 Fiber optic sfps.

Site 3 has

Only computers (no servers), 2 firewalls in HA with 2 fiber optic sfps.

Conditions:

Site 1 and site 2 has a database that always is synchronized, so the communication between the sites could not be interrupted, or at least a minimal time.

The computers of the 3 sites can connect to the database of site 1 and/or site 2. 

Behind the firewalls exist 2 switches, every computer has 2 nics, and connected to both switches to HA.

What could be the configuration in order to mantain the communication from the computers to the both sites, and of course the synchronization of the database between site 1 and 2.

Thanks !!!