An administrator attempts to increase the number of vCPUs in a virtual machine to 8. The configuration cannot be successfully completed.
What are two likely causes of this issue? (Choose two.)
A.
MS-DOS was selected as guest OS.
B.
The host has 4 processor threads.
C.
Virtual machine hardware version 7 was chosen.
D.
The vSphere 5.x implementation is using a Standard license.
Why A ? I think is wrong.
it is correct. When you setup a dos VM, you get only 1 CPU.
Have there ever been multi-core or even multi-socket systems with DOS. Can DOS even do multi-threading? I can’t remember.
That aside, you could use the process of elimination. The maximum allowed vCPUs with the Standard Edition is 8 (Enterprise/E-Plus are 32/64 respectively), so D is no limitation (yet). And HW version 7 support a maximum of 8 vCPUs, so once again no limitation (yet).
Since at any given time, it needs to be possible to allocate all vCPUs to physical CPUs, one cannot assign more vCPUs to a single VM than the server can allocate. (Anyone ever try moving a VM with a greater number of vCPUs to see what happens? Will it move but refuse to turn on, or will it not move at all?)
And as my first paragraph states, I don’t think it’s even technically possible for DOS to use more than one vCPU. Even if it could, can you think of a scenario when that could be needed? I can’t, I doubt VMware can’t either. So why implement it?
On a sidenote: What if VMware created a way to map multiple physical threads to one vCPU? Like two 3Ghz physical cores to 1 6Ghz vCPU? Some applications still perform better single threaded. I wonder if it’s possible…