Selecting No of Virtual sockets and No of cores per socket

CPUs in VM CreationI am setting up a new VM as web server with Windows 2012 R2. This new host came with 2 physical CPUs (INTEL XEON E5-2630V3 2011-3 2.40Ghz  8core ).
This web server will be accessed by about 5-10 users at any given time.
How do I decide what to select for No of Virtual sockets and No of cores per socket?
I was going to just go with default configuration (1 Virtual socket and 1 core per socket), but then I see the warning message "Changing the number of virtual CPUs after the guest OS is installed might make your virtual machine unstable".

Also what does it mean "The virtual CPU configuration specified on this page might violate the license of the guest OS". I purchased vSphere V6 Essentials which allows 3 Host Max - 2 CPU Per Host.
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sgleeAsked:
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David Johnson, CD, MVPOwnerCommented:
some software is licensed per core (physical cpu) so it is just a warning to help keep your business in compliance with software licensing.
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jmcgOwnerCommented:
Windows Server 2012 will allow you to add a processor core without reinstallation, possibly without even a reboot - if you've enabled "hot add". (ref: CPU Hot Plug Enable and Disable options [vmware.com]

The main reason for setting a number of virtual sockets is to conform to the licensing requirement of some software. For Windows Server Standard, your license usually limits you to two sockets

Starting out with one socket and one core-per-socket is a perfectly fine way to start. When you know more about your workload, you can increase the number of cores-per-socket to give the VM more CPU processing power to match the load.
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sgleeAuthor Commented:
@jmcg
Thanks for the information. I started creating a new VM with just 1 socket and 1 core per socket for now.
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Just use virtual sockets, unless you have a licensing requirement to use cores.

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
http://www.vmware.com/resources/techresources/10131

see here
http://www.gabesvirtualworld.com/how-too-many-vcpus-can-negatively-affect-your-performance/

http://www.zdnet.com/virtual-cpus-the-overprovisioning-penalty-of-vcpu-to-pcpu-ratios-4010025185/

also there is a document here about the CPU scheduler

www.vmware.com/files/pdf/perf-vsphere-cpu_scheduler.pdf

https://blogs.vmware.com/vsphere/2013/10/does-corespersocket-affect-performance.html
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gheistCommented:
Make it 2 vCPUs and never worry about uniprocessorHAL
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