I had a discussion around using FT in a stretched cluster (vSphere Metro Storage Cluster) environment. The main discussion point was around the use of “Host-VM” affinity rules. Some people appear to be under the impression that a Host-VM affinity rule can be created to ensure the primary and the secondary FT are divided between sites.
As I heard multiple people mentioning that this was possible I decided to test it. Unfortunately it is not possible. As soon as you enable FT on a VM and that secondary is started you will not see that secondary in the DRS Rules UI? Yes you can see the secondary if you look on a host level, but not in the DRS Rules workflow, this means it is not possible to ensure the secondary VM is bound to the second site.