How is the license key for Foglight for Virtualization Enterprise Edition worked out now?
The license keys are not worked out on cores. License keys are worked out on a per socket basis. So for example if there are 2 sockets with 8 cores each, you will need to purchase a 2 socket license.
From licensing perspective it does not matter if the monitored servers are active primary site servers or passive secondary site. You will need to purchase licenses for all monitored sockets on each site.