what is diffrence between cpu, core, vcpu

[challa]

what is diffrence between cpu, core, vcpu?

[a_p_]

CPU's and cores are physical, whereas the vCPU is a virtual representation/mapping for a virtual machine. When you assign a CPU t a VM in it's settings, this is called a vCPU. To the guest OS it looks like a real CPU but on the Hypervisor (ESXi, VMware Workstation, ...) it maps to a single core.

André

[DanielCunha26]

i guess your question is related to licensing, so this link may help:

http://www.vmware.com/download/eula/multicore.html

A core: multiple independent central processing units;

Still talking about licensing is worth to take a look on the new licensing model from vmware:

http://blogs.vmware.com/rethinkit/2011/08/changes-to-the-vram-licensing-model-introduced-on-july-12-...

regards

[Gav0]

Here is an article that helped me get my head around cpu, vcpu, vcore etc in Vsphere.

It's a bit dated but should help you conceptually:

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=101018...

[challa]

but my query is that,

1)if there is 1 physical cpu how many cores it may contain?

2)if there is core2 physical cpu how to calculate cores on it?

i mean supose for core2 cpu can we consider like,

    1 physical cpu ---> partitioned as 2 logical cores. if yes,can we use 2 cores for 2 diffrent vm's....

Thanks

CHALLA

[dextradeurf]

Bonjour,

Veuillez prendre note que je serai e congé usqu'au 2 avril.

Merci,

==========================================

Hi,

Please take note that i will be i vacation until Monday, April 2nd.

Thanks,

[a_p_]

1)if there is 1 physical cpu how many cores it may contain?

Depends on the ESXi version. With version 4.x there's a limit of 6/12 cores per CPU depending on the ESXi license. With ESXi 5.0 the limit does not exist anymore.

2)if there is core2 physical cpu how to calculate cores on it?

A Core2 DUO CPU has 2 cores, a Core2 QUAD has 4..

i mean supose for core2 cpu can we consider like,

    1 physical cpu ---> partitioned as 2 logical cores. if yes,can we use 2 cores for 2 diffrent vm's....

Depending on the VM's workload you can run even more VM's on this system. ESXi schedules the physical cores for use by the VM's. The maximum supported ratio is 25:1, where 25 VM's could run on a single core. However, that's a theoretical value nd will definitely not apply to the CPU you use.

André

Message was edited by: a.p. - fixed typos

[algubelli]

CPU = physical processors sockets on motherboard fix the cpu in that socket

Core = Physical CPU devided into cores ex:dual core mean in single socket u can conside as 2 Processors . Quard core mean 4

Vcpu = Assigning cpus to vm socket 1,2,4,6,8 like. vcpus it will be double r u can apply single also but it should not cross double of the physical sockets.

[madhav_VM]

Your reply is quite useful for clearing some silly but most important doubts. Intel core i5 CPU means it had 5 cores in it?.

[madhav_VM]

Each core is equal to how many vCPU's?. How can we classify that?.

[AmeenMunaff]

HI,

Hypervisor wont limit you, but from my experience its good to go for 4:1 proportion. ie. for one core - 4 vCPU

Regards

Ameen Munaf

[madhav_VM]

Hi Ameen,

It gives me more idea.  Thank you very much.