Hyper-V and per processor licensing in VM

One of the interesting things I found out in Hyper-V lately is regarding how the virtual processors are exposed to guests.

First of all if you are using VMM 2008, forget about the setting of “assiging a specific CPU type” to a VM:


I could not see any change in what a VM sees when I changed those settings. Either it does not work, or its so underneath that the VM is not aware of it (I did not have time to do deep CPU tests).

However what is interesting is that if you have a 2 proc quad machine as your host, then if you expose 2 virtual processors to your VM, the VM will see a single processor (of the same type as host) with 2 cores. If you assign 4 virtual processors, it will see a single processor with 4 cores. This is especially useful in light of per processor (e.g. SQL) licensed MS products. In VMWare (as far as I was told) you cannot assign vCPUs to specific cores so they do not travel over physical CPUs, and the VM sees more then 1 CPU even if you have a quad core machine. In light of MS licensing then you need to license the VM as per the physical procs it sees.

Here is a bunch of screenshots to prove what Ben described here: http://blogs.msdn.com/virtual_pc_guy/archive/2008/07/18/processor-topology-inside-of-hyper-v-virtual-machines.aspx

CPUs on host:


VM virtual CPU Settings:


CPU as seen in VM:



~ by alipka on December 17, 2008.

One Response to “Hyper-V and per processor licensing in VM”

  1. […] is treated as a separate CPU It does, but I think you need to use SCVMM 2008 R2 to create VMs. https://alipka.wordpress.com/2008/12/…censing-in-vm/ Reply With Quote […]

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