CPU Esxi Host

I have a ESXi host with 1 CPU, 6 core.
What is the best CPU configuration on VM machines I put on this ESXi cough
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There is not a best CPU configuration. It depends on your needs and on the physical resources.

It depends also on the operating system you are planing to install on that ESXi host.

Take a look at this link for more details: https://florenttastet.wordpress.com/2014/06/29/choosing-hardware-for-use-as-an-esxi-host/

Hope it helps. Regards.
As a rule of thumb, assign as less cpu's as possible.
NoAtMidAuthor Commented:
Thanks. :-)
 will be running Windows Server 2008 & 2008R2 win7 pro. The plan was to bring in 20 to 25 machines. Should I put oppo 1 CPU with 1 cor for each vm machine?
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Always starts with 1 vCPU (sockets), and increase if required.

vSMP (virtual SMP) can affect virtual machine performance, when adding too many vCPUs to virtual machines that cannot use the vCPUs effectly, e.g. Servers than can use vSMP correctly :- SQL Server, Exchange Server.

This is true, many VMware Administrators, think adding lots of processors, will increase performance - wrong! (and because they can, they just go silly!). Sometimes there is confusion between cores and processors. But what we are adding is additional processors in the virtual machine.

So 4 vCPU, to the VM is a 4 Way SMP (Quad Processor Server), if you have Enterprise Plus license you can add 8, (and only if you have the correct OS License will the OS recognise them all).

If applications, can take advantage e.g. Exchange, SQL, adding additional processors, can/may increase performance.

So usual rule of thumb is try 1 vCPU, then try 2 vCPU, knock back to 1 vCPU if performance is affected. and only use vSMP if the VM can take advantage.

Example, VM with 4 vCPUs allocated!

My simple laymans explaination of the "scheduler!"

As you have assigned 4 vCPUs, to this VM, the VMware scheulder, has to wait until 4 cores are free and available, to do this, it has to pause the first cores, until the 4th is available, during this timeframe, the paused cores are not available for processes, this is my simplistic view, but bottom line is adding more vCPUs to a VM, may not give you the performance benefits you think, unless the VM, it's applications are optimised for additional vCPUs.

See here

see here


also there is a document here about the CPU scheduler


NoAtMid and Andrew are right. You should try to use as less resources as you can for the virtual servers. This is not just about CPU, but also about RAM, etc... However, sometimes you need more resources, and if the physical machine has a lot of free resources it shouldn't be a problem.

Hope it helps. Regards.
Tony GiangrecoCommented:
I agree with gplana,

The configuration ultimately depends on the load that is placed on each VM. You may want to setup a few VM's and install apps and monitor them for performance issues. I'd suggest monitoring them during peak usage times so you see usage peaks and can capture stats from the Microsoft Performance stats.  If you see performance takes a hit you in a negative manner, you can change the resource allocation and test it again for an improvement.

Hope this helps!

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NoAtMidAuthor Commented:
Thanks to all. I think I have a good understanding how to do it now. :-)
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