I have 2 vsphere version 5 configured as HA. I have a san storage connected to each vsphere.
Each vsphere have 1 hba and 4 nic cards.
If I unplug one vsphere from the power cord .... HA works and migrates all Vm guest machines to the second vsphere.
If I just unplug the HBA cable from one Vsphere (to simulate a hba connection problem) ... those VM guest machine don´t migrate to the second vsphere .