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How can I increase the cpu to the virtual machines?

I am trying to increase the cpu to the VMS,, could you please explain how to perform this activity?
and what are all the things we need to consider for this?
what is the Socket and Core with respect to this?
if we increase the socket what happens? or if we increase the core what happens?
how to increase the vm performance with respect to this?

please help.
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satheesh kumar
Asked:
satheesh kumar
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1 Solution
 
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Please see the other post.

You may need to turn off the VM, and edit the VM settings, and change CPU and Cores.

You may also want to read the following:-

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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David Johnson, CD, MVPOwnerCommented:
Sockets are physical cpu's, each cpu has their own memory
Cores are within the same cpu. each core shares memory
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
do you require any further assistance to close this question?
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satheesh kumarAuthor Commented:
As always, your answer is very informative,

Thanks for your valuable time and patience.
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satheesh kumarAuthor Commented:
Thanks a Ton,

I took some time to read the content,

This is the best solution thanks.
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