How it works…

Sometimes, you may see that Consumed Host Memory is greater than Active Guest Memory. The reason for this is that for physical hosts that are not overcommitted on memory, Consumed Host Memory represents the highest amount of memory usage by a VM. It is possible that in the past, this VM was actively using a very large amount of memory.

Because the host physical memory is not overcommitted, there is no reason for the hypervisor to invoke ballooning or host-level swapping to reclaim memory. Therefore, you can find the VM in a situation where its active guest memory use is low, but the amount of host physical memory assigned to it is high. This is a perfectly normal situation, so there is nothing to be concerned about.

If the Consumed Host Memory is less than or equal to active guest memory, this might be because the active guest memory of a virtual machine might not completely reside in the host physical memory. This might occur if a guest's Active Memory has been reclaimed by the balloon driver, or if the VM has been swapped out by the hypervisor. In both cases, this is probably due to high memory overcommitment.