Vmware Affinity Rules:

Keep Virtual Machines Together - e.g. keep an IIS (Web Server) and SQL Server together on the same host.

VM - VM - is either keeps machines together or apart. (e.g. like two DCs keep on different hosts)

I guess is related to HA

DRS & HA e.g. your Cluster (if enabled)

It seems to me VM to VM is applicable only if you have Failed ESX Host, ...Then the VMs will have to be restarted on the other ESX Host

So ,On the screenshot above which VMs will restart first? the ones in VM-Group1 or the ones in VM-Groups2 ?

Thank you

DRS and HA rules apply to both.

I believe they mean VMs in Group 1  will not restart until they meet certain Conditions , then   VMs in Group 2 will restart.

Yes, like you will need to have SQL Services Started first before Web Servers.

and you will need Domain Controllers and DNS Services started before anything else...

look inwards at your infrastructure, as to what needs to be started before it will all work.

vSphere will also be dependant upon DNS, maybe DHCP, Firewalls and Routers, if these are all virtual.

It sounds like it is the same function as VApps

Thank you