Hyper V Processor Allocation

[guest]

If I have two Xeon Quadcore E5506 Processors, how many virtual processors can I allocate to the VMs?

[guest]

Theoretically, there is really no upper limit to how many virtual CPU's you can assign to virtual machines. The official recommendation from the Hyper-V product team is not to exceed more than 8 virtual CPU's per each physical CPU (i.e. core).

Based on that calculation the limit will in your case be:

2 * 4 * 8 = 64 virtual CPU's

And if your server supports and you enable hyper-threading, the calculation will be:

2 * 4 *2 *8 = 128 virtual CPU's

Now, this "rule of thumb" is a guiding recommendation more than anything, since different server roles and application might require more or less CPU time. In a general perspective this will most surely apply, since many virtual servers just sit there, and the real bottlenecks are usually located elsewhere, such as RAM, disk I/O performance and so on.

For reading the official material, I refer you to the article on the Hyper-V product team blog:

http://blogs.technet.com/b/virtualizati ... reads.aspx

[guest]

Your Xeon E5506 is an Intel Penryn-EP processor with 4 cores, single thread.

http://ark.intel.com/products/37096

So the limit is 2 (processor) * 4 (Cores) * 1 (Thread per core) * 8 = 64 virtual processors.


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[guest]

According to this is. Is it the same as logical processors? How many logical processors does I have? Also with 4 X Windows Server 2003 32 Bit VMs. How many logical processors can I allocate for each?

[guest]

Microsoft currently supports a max of 4 virtual processors for a VM.

Microsoft provides a maximum for virtual processors per logical processor, where a logical processor equals a core, or thread.(From link on Mike's post above)

Depending on the VM's OS, it may be lower than 4. http://technet.microsoft.com/en-us/libr ... 4868(WS.10).aspx

Keep in mind adding more vCPUs to a VM does not guarantee better performance, it can reduce performance and/or cause other issues with the guest OS in the VM.