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mazixo
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Contributor

CPU

hi

I want to know abut cpu virtuLzation on ESXi 5.  what is the deffrence between of socket and core . relation of this parameters with physical cpu .limitaton of vCPU for vm  and how assign physical dedicated cpu for a vm! and much more.....

Love,Life,Freedome is iranain's right Maziyar Khamenh
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a_p_
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A socket is a processor which contains a number of cores. Your ESXi host will show this as logical CPUs (i.e.  no. of sockets x no. of cores per socket). HyperThreading doubles the logical CPUs. Each vCPU you configure for a VM maps to a single logical CPU. For VMs with vCPUs and Cores-per-Socket configured, you'd multiple these two values.

Although it is possible to pin physical cores to a VM, I would recommend not to do this. The CPU scheduler in ESXi does a pretty good job and you should only manually pin cores to VMs if there's no way around.

André

mazixo
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whats differences between a vm with  2 sockets and 4 core  or a vm with 4socket and 2core ?is there any performance deffrance ?is it cuse to crate extra load on one of the physical cpu?

Love,Life,Freedome is iranain's right Maziyar Khamenh
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a_p_
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The difference is just the presentation to the guest OS, whether it sees 2 quad-core CPUs or 4 dual-core CPUs.

Take a look at http://kb.vmware.com/kb/1010184 which explains some of the use cases for this feature.

André

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jrmunday
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whats differences between a vm with  2 sockets and 4 core  or a vm with 4socket and 2core

Performance will be the same, but a valid use case for considering this variation is if you have an application running on the guest VM, and the application is licenced per socket - it will obviously be cheaper to have two sockets with 4 cores than 4 sockets with 2 cores.

is it cuse to crate extra load on one of the physical cpu?

The CPU cycles should be scheduled evenly acroass all the physical cores (especially if you are using the latest build of 5.0) - this includes an important fix which addresses a NUMA rebalance issue and makes a significant performance increase.

You will only suffer from a specific physical CPU under load if you have configured any CPU afinity (not recomended without a valid use case).

vExpert 2014 - 2022 | VCP6-DCV | http://www.jonmunday.net | @JonMunday77
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