Solved

Co-Relation between vCPU & Server cores

Posted on 2011-02-22
6
869 Views
Last Modified: 2012-05-11
Hi.

Can some one please explain the relationship between Server cores & vCPUs.

The servers which we use for virtualizaton are Dual core or Quad core or 2x Quad Core.

When we create a VM on the Hypervisor, it asks for vCPU.

How do we best optimally use the hardware.

For example, if a server requires Quad core processor & if i have to virtualize the server, how many vCPUs do i allcate so as to not to impact the performance.

Is there any relationship between them?

Regards,

Rohan
0
Comment
Question by:Rohan_Singnapurkar
  • 3
  • 2
6 Comments
 
LVL 95

Accepted Solution

by:
Lee W, MVP earned 500 total points
ID: 34957822
Each Core is a CPU.  Virtualization doesn't provide multiple cores to the VMs, it sees them as individual CPUs.  So if you have a server/app that wants 4 CPUs (or a quad core), you have to assign 4 cores.

Put another way, a multi-Core processor is really just one "chip" with multiple CPUs on it.  So Virtualizations products should allow you to assign up to the number of cores you have (viewing each core as a CPU)
0
 

Author Comment

by:Rohan_Singnapurkar
ID: 34958063
can you please elaborate on the same by providing one example.
0
 
LVL 95

Expert Comment

by:Lee W, MVP
ID: 34958275
I have provided two.  If you don't understand what I'm saying, please clarify what you find unclear and I can try to elaborate on that.
0
Ransomware-A Revenue Bonanza for Service Providers

Ransomware – malware that gets on your customers’ computers, encrypts their data, and extorts a hefty ransom for the decryption keys – is a surging new threat.  The purpose of this eBook is to educate the reader about ransomware attacks.

 

Author Comment

by:Rohan_Singnapurkar
ID: 34958361
Does this mean that in Virtualization, each core is treated as a CPU. If so then wot is the co relation between a CPU & a vCPU.

For example an Hyper V supports 6 - 8 VMs per core. Does this mean that 1 CPU = 8vCPU.

Also if I have to create a server which in a physical environment requires Quad core, should i then be assigning 32 vCPUs to the Server as we cannot assign CPUs in a virtual environment.
0
 
LVL 95

Expert Comment

by:Lee W, MVP
ID: 34958410
> Does this mean that in Virtualization, each core is treated as a CPU.
My response started with "Each Core is a CPU."

you seem to be thinking of the "chip" installed in the computer as the CPU.  It's not.  It's more of an "add-in" card that contains 2, 3, 4, 6 or more CPUs - these are generally referred to as "cores".

a vCPU is a virtual CPU - a single virtual core.

Total Physical Cores = Total Virtual CPUs
0
 

Expert Comment

by:ACourvoisier
ID: 37854834
Hi,

A large explanation there, in english. Very well explained (but I don't access to the images):

http://complaintsincorporated.com/2011/02/21/vcpu-pcpu-lcpu-ht-and-you/

of 21 feb. 2011.

In matter, I understand that VMware recommanded to allow 4 vCPU max per core.
0

Featured Post

Ransomware-A Revenue Bonanza for Service Providers

Ransomware – malware that gets on your customers’ computers, encrypts their data, and extorts a hefty ransom for the decryption keys – is a surging new threat.  The purpose of this eBook is to educate the reader about ransomware attacks.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

VMware Update Manager(VUM) “error code: 15” during ESXi 6.0 Remediate update in VUM operation
It Is not possible to enable LLDP in vSwitch(at least is not supported by VMware), so in this article we will enable this, and also go trough how to enabled CDP and how to get this information in vSwitches and also in vDS.
How to install and configure Citrix XenApp 6.5 - Part 1. In this video tutorial we have explained step by step installation of Citrix XenApp 6.5 Server on Windows Server 2008 R2 is explained in this video. We have explained the difference between…
In this video tutorial I show you the main steps to install and configure  a VMware ESXi6.0 server. The video has my comments as text on the screen and you can pause anytime when needed. Hope this will be helpful. Verify that your hardware and BIO…

778 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question