CPU count - Win 2K8 Std on VMware

[adrianych]

Hi, I need some advise as I am currently reading up on VMware 5.0 Essential Plus and the microsoft Windows 2K8 editions comparison.

Here's what I've think I understood :

- taking I have a server with 2x CPUs with 6 cores each (total 12 cores)

1. VMware 5.0 allows up to 8 vCPU (means I can create a VM with 8GB RAM and 8 "CPUs")

2. Windows 2008 R2 Std allows only up to 4 X64 sockets and 32GB RAM

Does it mean that I cannot use the above config ?

[Virtualinfra]

You should be able to create a VM without any problem with 8 vCPU and 32 GB RAM. if the guest os supports it.

Note:-

Windows 2008 CPU limit ( socket) with editions

Standard: 4
Enterprise: 8
Datacenter: 64

No limit for logical cores only limit for sockets

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[adrianych]

So does this means that the O/S does not actually take 1 vCPU as 1 socket ?

Is there any vCPU to socket "conversion" or "translation" matrix ?

[Virtualinfra]

refer the below link for how to Set the number of cores per CPU in a virtual machine

To implement this feature:
1.Power off the virtual machine.
2.Right-click on the virtual machine and click Edit Settings.
3.Click Hardware and select CPUs.
4.Choose the number of virtual processors.
5.Click the Options tab.
6.Click General, in the Advanced options section.
7.Click Configuration Parameters.
8.Include cpuid.coresPerSocket in the Name column.
9.Enter a value (try 2, 4, or 8) in the Value column.

Note: Ensure that the number of vCPUs is divisible by the number of  cpuid.coresPerSocket in the virtual machine. That is, when you divide the number of vCPUs by the number of cpuid.coresPerSocket, it must return an integer value. For example, if your virtual machine is created with 8 vCPUs, coresPerSocket can only be 1, 2, 4, or 8.

The virtual machine now appears to the operating system as having multi-core CPUs with the number of cores per CPU given by the value that you provided in step 9.

10.Click OK.
11.Power on the virtual machine.

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1010184

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[adrianych]

Thanks....now I am even more confused, FYI, most of the time, I only allocate 2 or 4 CPUs per VM based on "Vendor recommended".

But if on VMware....with the bombshell that you dropped....

Note: Ensure that the number of vCPUs is divisible by the number of  cpuid.coresPerSocket in the virtual machine. That is, when you divide the number of vCPUs by the number of cpuid.coresPerSocket, it must return an integer value. For example, if your virtual machine is created with 8 vCPUs, coresPerSocket can only be 1, 2, 4, or 8.

My current servers runs 1x or 2x Intel 6 core CPUs...how would I ever get an interger ? 2/6 or 4/6 or 2/12 or 4/12 was the max based on VMware 4.1 Essential plus (or any version before June 2011).

Actually, my initial question was more on Microsoft licensing on vCPUs....now its developed further....

[Virtualinfra]

For your intial question the answer is

Windows 2008 CPU limit ( socket) with editions

Standard: 4
Enterprise: 8
Datacenter: 64

No limit for logical cores only limit for sockets

you can configure 4 vcpu and increase the number of cores as the KB provided.

For your current confusion.

Note: Ensure that the number of vCPUs is divisible by the number of  cpuid.coresPerSocket in the 
virtual machine.That is, when you divide the number of vCPUs by the number of cpuid.coresPerSocket, 
it must return an integer value. For example, if your virtual machine is created with 8 vCPUs, 
coresPerSocket can only be 1, 2, 4, or 8.

From virtual machine

1 vcpu = 1 socket

so 1 socket(vCPU) can have 1, 2, 4 or 8 cores.

if you have 2 vCPU you can configure 2 core or 4 cores or 8 cores.

Do Not compare with physical machine sockets and processors. the point clearly states that you need to divide the number of core with number of vcpu and not with physical cores you have.

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[adrianych]

So what is

i. Physical socket ?

- Noramlly 1 server have 2 intel CPUs, that = 2 sockets ?

ii. Physical core ?

- Each Intel Xeon X series eg X5650 has 6 cores, for my server = 6x 2 = 12 cores ?

iii. vCPU

- ??

iv. "allocated CPU in the VM" ?

- I normally allocate 2 CPU for file server thats = ??

- I normally allocate 4 CPU for file SQL thats = ??

v. core

- ??

[Virtualinfra]

iii. vCPU

- ??

iv. "allocated CPU in the VM" ?

- I normally allocate 2 CPU for file server thats = ??

- I normally allocate 4 CPU for file SQL thats = ??

v. core

- ??

By Default 1vCPU = 1 core

- I normally allocate 2 CPU for file server thats = 2 cores

- I normally allocate 4 CPU for file SQL thats = 4 cores

as per the KB if you increase the cores to 2 (cpuid.coresPerSocket =2)

then it change like this.

- I normally allocate 2 CPU for file server thats = 4 cores

- I normally allocate 4 CPU for file SQL thats = 8 cores

this clarifies...

[adrianych]

Hmmm.....

Does it mean that even if I allocate "2x CPUs" to my VM file server, on a machine that has 3 CPUs, I am using 6 vCPUs ?

[Virtualinfra]

The condition is clearly state here in the below note That is, when you divide the number of vCPUs by the number of cpuid.coresPerSocket, it must return an integer value.

So you not allowed to use 3, which wont fetch you a integer value.

Note: Ensure that the number of vCPUs is divisible by the number of  cpuid.coresPerSocket in the virtual machine.That is, when you divide the number of vCPUs by the number of cpuid.coresPerSocket, it must return an integer value. For example, if your virtual machine is created with 8 vCPUs, coresPerSocket can only be 1, 2, 4, or 8.

Does it mean that even if I allocate "2x CPUs" to my VM file server, on a machine that has 3 CPUs, I am using 6 vCPUs ?

Actually small correction here.

You have 3 vCPU ( vCPU referred to sockets) and you allocate 2x for 1 vCPU. then you will using 6 cores not 6 vCPU.

Note: - You dont have option to select 3 vCPU. you have got option to selecte is 1, 2 ,4, 8 etc.

same as physical server difference between processors and cores thats it.

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[adrianych]

thanks anyway.

I just have to have my vHead screwed to my vNeck and get a good nights vSleep.

else its going to be an Intel CPU of 6 cores with 64GB RAM running on a VM with 3 CPUs of 3vCPU using 18GB vRAM but cannot work as we did not have a vMouse and vKeyboard....

Anyone tried installing Win2K8 hyper-v on a VMware machine so that each hyper-v installs a ESXi to install 3 more hyper-v?

[rickardnobel]

Note also that on vSphere 5 you do not have to edit the VMX file to configure this, there is options for setting the socket vs core in the ordinary vSphere Client GUI.

[sergeadam]

When you configure a VM, each vCPU is will appear as a CPU in the guest OS. So allocating 8 vCPU to a guest will show as 8 single-core CPUs to the guest OS. By default, ESX configures 1 core per vCPU. That can be modified on a guest level. So your 8 vCPU guest, you could allocate 2 vCPU and assign 4 cores per CPU. Your are still using 8 cores, but the guest sees 2 4-core CPUs. It makes no difference in the way ESX behaves, but can make a world of difference in the guest licensing.

[Shashi112]

Hi Folks ,

I have a requirement to build VM with 6 cpus , does it mean that I have to allocated vcpus as 8.

Can I configure is as below :

No. of virtual sockets 3

No.of cores per scoekt : 2

ESX host config :

No. of Physical Socekts is : 2

cores per socket  : 8

Will my windows Std edition work as expected or will I have issues.

Thanks in Advance !!..

Shashi

[adrianych]

U restarted a very old thread....

Number of CPUs in OSe depends on the number of vCPU u are going to allocate, not the physical ones.

FYI, I could recommend that you try 2x2 CPUs.

This is the more standard CPU config if you are worried about issues.

It should work properly. Then power off, take a snapshot, increase RAM & CPU to desired if there is performance issues.

At least if anything goes wrong, you can still roll back to the point before you increased the vCPU and RAM.

Hope this helps.