Solved

Co-Relation between vCPU & Server cores

Posted on 2011-02-22
6
900 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
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 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
The Eight Noble Truths of Backup and Recovery

How can IT departments tackle the challenges of a Big Data world? This white paper provides a roadmap to success and helps companies ensure that all their data is safe and secure, no matter if it resides on-premise with physical or virtual machines or in the cloud.

 

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

Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

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

Suggested Solutions

Title # Comments Views Activity
ESXI home lab network setup (KISS) 12 212
Converting Hyper-V 2012 R2 VM to 2016 5 197
Hyper-V VM not connected 1 143
unable to reinstall SCVMM 2012 R2 - SQL errors. 5 39
Will try to explain how to use the VMware feature TAGs in the VMs and create Veeam Backup Jobs using TAGs. Since this article is too long, I will create second article for the Veeam tasks.
Giving access to ESXi shell console is always an issue for IT departments to other Teams, or Projects. We need to find a way so that teams can use ESXTOP for their POCs, or tests without giving them the access to ESXi host shell console with a root …
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…

756 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