[CentOS-virt] How many virtual guest 'cpus' can a core duo 'quad' core support

Alexander Dalloz ad+lists at uni-x.org
Wed Feb 22 03:43:01 EST 2012

Am 22.02.2012 08:46, schrieb Andreas Reschke:
>> The maximum you can assign to a single VM is the amount of CPUs
>> > visible to the KVM host.  So a quad core is shows as 4 CPUs to the OS,
>> > so you could assign 4 vCPUs to a guest.  To see how much is available
>> > and seen by KVM run # virsh nodeinfo.
>> > 
>> >  - Trey

> Hello,
> I think thats not correct. I my case I have a HP N36L Server with one 
> Dualcore Prozessor and 4 guest running. You can overbook the prozessor.
> Maybe the performance goes down.
> Gruß 
> Andreas Reschke


Trey didn't say anything different.

You can assign at max the number of physical cores of the KVM host to
any VM. So if your KVM host has 4 cores you can have 1 VM with 4 vCPUs.
And another VM with 4 vCPUs as well. Then you are overbooked.


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