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

Wed Feb 22 08:43:01 UTC 2012
Alexander Dalloz <ad+lists at uni-x.org>

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

Andreas,

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.

Alexander