If isolation response is set to “shut down” or “power off’ then when an ESXi host is isolated, VM’s are powered off or shutdown as a result of trigger of isolation response. Now the question is how HA keep tracks of which VM were powered off/shutdown due to this trigger.

The answer to this question is as follows: When a VM is shutdown/powered off due to triggering of isolation response than the host that has isolated remove entries of those VM’s from power on file and creates a PER virtual machine file INSIDE a directory called “powered off”. HA reads these FILES to identify the state CHANGE of the VM’s and based on that it takes decision to restart those VM’s.

This is necessary because, suppose when a host is isolated and at the same time if someone has manually issued a shutdown/powered off command to a VM, then HA will not restart that VM. There will be no file created for that VM by isolated host because it has been manually shut down.

If isolation response is set to “shut down” or “power off’ then when an ESXi host is isolated, VM’s are powered off or shutdown as a result of trigger of isolation response. Now the question is how HA keep tracks of which VM were powered off/shutdown due to this trigger.

The answer to this question is as follows: When a VM is shutdown/powered off due to triggering of isolation response than the host that has isolated remove entries of those VM’s from power on file and creates a per virtual machine file inside a directory called “powered off”. HA reads these files to identify the state change of the VM’s and based on that it takes decision to restart those VM’s.

This is necessary because, suppose when a host is isolated and at the same time if someone has manually issued a shutdown/powered off command to a VM, then HA will not restart that VM. There will be no file created for that VM by isolated host because it has been manually shut down.