A resource pool exists with a memory reservation of 14GB. The pool has 5
single-processor virtual machines and 2 dual-processor virtual machines. Each of these
VMs has a memory reservation of 2GB. When an attempt is made to power on the
seventh Virtual Machine in the resource pool, a single-processor VM with a 2GB
memory reservation, a warning states there is insufficient memory resources to power on
the VM. The reason for this warning is?

A.
The VMkernel device drivers are consuming memory

B.
Service Console memory has not been increased to accommodate the virtual machine
workload

C.
Overhead memory for the VMs is consuming memory in the resource pool

D.
Memory reservations for the VMs are consuming memory in the pool

Explanation:
vSphere Resource Management Guide ESX 4.0 ESXi 4.0 vCenter Server 4.0, page 28
Virtual machines incur overhead memory. You should be aware of the amount of this
overhead.
Table 3-2 lists the overhead memory (in MB) for each number of VCPUs.
Table 3-2. Overhead Memory on Virtual Machines
Memory
(MB) 1 VCPU 2 VCPUs
2048 137.81 198.20
There are currently 6 virtual machines powered up, consuming
6 x 2GB reservations = 12GB
4 single processor machines, = 4 x 137.81 MB = 552MB
2 dual processor machines, = 2 x 198.20 MB = 396 MB
Total memory consumed is 12.92 GB, so total memory available = 1.08GB
When an attempt is made to power on the seventh Virtual Machine in the resource pool,
an additional 2 GB + 137 MB is required. Since this is not available, the machine cannot
start.