So we ran into this last night and are trying to work through why things happened the way they did – which is to say, why we had some support personnel on the phone who said “it shouldn’t do that.” The long and short of what a split-brain scenario is this:
You have two hosts with VMs running in an HA cluster. Host 1 gets completely isolated from the network – no service console, no guest net connections, nothing – but the VMs are still running on it. If you have your HA settings set up to not power down those virtual machines on isolation, HA has already started up those VMs on Host 2 – and when Host 1 reconnects to the network (with it’s never-shut-down-VMs) you’ve now got two VMX processes running in memory on two hosts. This is not good.
