kvm in proxmox can assign maximum 2 cores

[mikhmv]

Hi,

I tried to create VM (KVM) with 4 cores. In result i have got VMs with only 2 cores. Original machine have 8 cores.
Probably, It is bug....

P.S. If create VM with 2 cores it is have 2 cores.

 

[fromport]

Hi,

I tried to create VM (KVM) with 4 cores. In result i have got VMs with only 2 cores. Original machine have 8 cores.
Probably, It is bug....

P.S. If create VM with 2 cores it is have 2 cores.

No problem here:
Just created a jeos vm with 4 cpu's (host has 8 cores)

$ grep processor /proc/cpuinfo
processor    : 0
processor    : 1
processor    : 2
processor    : 3

If you look in te config file of the vm in question, how many cpu's
does it specify ?

# grep smp /etc/qemu-server/101.conf (which in my case is the jeos image i created earlier)
smp: 4

 

[tom]

Hi,

I tried to create VM (KVM) with 4 cores. In result i have got VMs with only 2 cores. Original machine have 8 cores.
Probably, It is bug....

P.S. If create VM with 2 cores it is have 2 cores.

you can assign 16 cpu´s currently, will be more soon. but make sure your guest OS can handle this.

e.g. winxp only shows 2 cpus.

what OS do you have on the guest?

 

[mikhmv]

Hi Tom,

Yes, I am using windows XP.

but before this on this machine (with 8 cores) was same XP which was installed from same disk......

Do you think that XP under KVM can't recognize more than 2 cores? (I don't know).

FromPort: I didn't try linux guest.

 

[fromport]

Do you think that XP under KVM can't recognize more than 2 cores? (I don't know).

I just installed XP (pro) on a guest which i gave 4 cpu's and cpu-z reported only 2 cpu's.

So yes, i do think the limitation is in windows.

 

[mikhmv]

thanks.

I already 3 times tried to install 4 cores....
I will not try again.....

 

[fromport]

thanks.
I already 3 times tried to install 4 cores....
I will not try again.....

I gave both a windows2008 install and a windows7 install 4 cpu's.
Only windows 2008 recognized the 4 cpu's

just fyi

 

[mikhmv]

fromport: Thanks for research

 

[tom]

Hi Tom,

Yes, I am using windows XP.

but before this on this machine (with 8 cores) was same XP which was installed from same disk......

Do you think that XP under KVM can't recognize more than 2 cores? (I don't know).

FromPort: I didn't try linux guest.

The licensing of windows xp allows to run two cpu sockets. so if you install on a physical hardware with 2 sockets (each 4 cores) you will see 8 cpu in windows xp.

If you install on KVM you can assign cpu sockets means if you select 4 cpu´s its like assigning 4 sockets which is not possible - only 2 are shown due to the license of microsoft.

 

[mikhmv]

Tom: I used computer with 2 sockets with 4 core each. Originally on this computer was WinXP and it recognized all 8 cores. But in KVM only 2.

 

[virtualsid]

Tom: I used computer with 2 sockets with 4 core each. Originally on this computer was WinXP and it recognized all 8 cores. But in KVM only 2.

I think this is due to the way MS do licensing.

With the two sockets with Windows XP as the host, Windows knows it's two physical devices, with quad cores, so allows it.

With KVM, it probably emulates it as four totally separate sockets.

It's probably worth reading the MS site, e.g. http://www.microsoft.com/licensing/highlights/multicore.mspx

Sid