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How are CPU's allocated in ESXi
I have a Dual Xebn Quad Core HP DL360 G5
I am running VMware ESXi
If I install a 32bit Windows Server 2003 guest and assign it 1 CPU how is this CPU mapped to the cores in the hardware ?
Is it just as it says - a virtual CPU - that really then gets processed by all 8 cores ?
Or is it assigned (or can it be) to one core only?
Furthermore, If I install only 32 bit guests - am I 'wasting' the power of the hardware?
Would I get better performance from a 64bit Windows Server 2003 guest than a 32bit guest ?
Regards
Graeme
I am running VMware ESXi
If I install a 32bit Windows Server 2003 guest and assign it 1 CPU how is this CPU mapped to the cores in the hardware ?
Is it just as it says - a virtual CPU - that really then gets processed by all 8 cores ?
Or is it assigned (or can it be) to one core only?
Furthermore, If I install only 32 bit guests - am I 'wasting' the power of the hardware?
Would I get better performance from a 64bit Windows Server 2003 guest than a 32bit guest ?
Regards
Graeme
ASKER
OK thanks Lars
In that case - 2 further questions:
with 8 cores - does this mean I can only run up to 8 VM's with single vCPU's ?
my 32/64 bit query: If a VM does tie up a single core - should I not be using 64 bit guests instead of 32 bit? Will a 64bit VM perform better than a 32bit VM ?
Graeme
In that case - 2 further questions:
with 8 cores - does this mean I can only run up to 8 VM's with single vCPU's ?
my 32/64 bit query: If a VM does tie up a single core - should I not be using 64 bit guests instead of 32 bit? Will a 64bit VM perform better than a 32bit VM ?
Graeme
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ASKER
Thanks again Lars - Graeme
One vcpu in the guest VM equals one cpu core of the host. When the VM is running, each of the vcpus inside the VM will run on different physical cpu cores. If a VM is allocated a single vcpu, it will be scheduled to run on the physical cpu core with the most available resources.
You can give a single guest a maximum of 4 vcpus, but you should always start with a single vcpu and only give your guest more vcpus if it really needs them.
Giving your guests more than 1 vcpu has some virtualization overhead and might in many cases give not equally good performance as if you give it a single one. Even though ESX as relaxed co-scheduling (compared to strict co-scheduling) you should always start out with a single vcpu.
Lars