An organization has a HA/DRS cluster containing a mixture of ESXi 4.1 and 5.5 hosts in the
cluster. An ESXi 5.5 host has failed and HA attempted but failed to restart the virtual machines on
another host. HA admission control is disabled.
What condition could result in this behavior?
A.
A virtual machine has an incompatible hardware version
B.
Insufficient resources exist on the remaining ESXi hosts
C.
vMotion migration is not supported between ESXi 5.5 and 4.1 hosts
D.
HA failover is not supported between ESXi 5.5 and 4.1 hosts
Explanation:
http://blogs.vmware.com/vsphere/2011/10/mixing-esxesxi-versions-in-an-hadrs-cluster.html
So in conclusion, running mixed ESX/ESXi versions in an HA/DRS cluster is supported but be careful not to mix older VMs running virtual hardware 3 or VMware tools 3 in the same cluster with ESXi 5.0 hosts. It is okay (if not recommended) to upgrade VMware Tools while running in a mixed mode as long as all the hosts are running ESX/ESXi 4.x or higher, but avoid upgrading virtual hardware and VMFS volumes until after all hosts are running ESXi 5.0.
Since HA admission control is disabled, HA cannot guarantee that sufficient resources exist in the cluster. Hence, B could be a valid choice as well.
‘B’ is NOT an option here because, even if resources on remaining hosts are low, it would simply take longer to restart VMs due to the need for reclaiming RAM from the “balloon” driver in running VMs, memory swapping, etc.
So, ‘A’ is the only plausible option to choose as a correct answer.
In my oppinion “B” is the correct answer.
B: If the VMs have CPU/Mem reservations in place, the remaining hosts might not have sufficient capacity to fulfill the failed VMs reservations.
A:The cluster is running with a mixture of 4.1/5.5 hosts. the question did not specify that the last/only 5.5 host has failed thus no compatible host is left.
J.
B. The question says it failed to restart the virtual machineS(plural) not just a particular virtual machine with an incompatible version so B is the most reasonable answer
I have to agree with Carlos, if there are not enough resources available (baloon driver or not) the VM’s will not be able to start