[PVE-User] KVM options menu

Martin Maurer martin at proxmox.com
Wed Sep 16 08:42:44 CEST 2009

> -----Original Message-----
> From: pve-user-bounces at pve.proxmox.com [mailto:pve-user-
> bounces at pve.proxmox.com] On Behalf Of Tony Zakula
> Sent: Dienstag, 15. September 2009 16:17
> To: pve-user at pve.proxmox.com
> Subject: [PVE-User] KVM options menu
> Hi,
> I just have a quick question.  I have looked for documentation for
> this, but could not seem to find it.  On the options tab for the KVM
> machine, the three options:
> Disable KVM

If you disable KVM, just qemu emulation is used - means no hardware virtualization support. 
(not really tested, use it just for debugging)

> Disable ACPI

Means what it stands for. If you disable ACPI you can install guests not capable of ACPI. Former versions ago windows works better without ACPI, but this already some time ago.

> Freeze CPU at startup

By selecting this, you can start the VM and it is freezed. Now bring up the VNC console and the monitor. Now you can type continue and you will see the VM starting as usual but you are already prepared to press F8 or whatever you need. Very useful for debugging dead windows. But do not forget to uncheck after you are finshed. 

> Is there any recommendation on these?  I recently disabled kvm on a
> debian install and the processor was at a continuous 100%.  I am trying
> to understand and tune this for testing to possibly put in a production
> environment.
> Right now, I have two machines in a cluster with quad core processors,
> 4gb ram and one sata disk each.  I installed the bare metal proxmox,
> and plan to use debian kvms for all virtual machines.  The debian kvms
> have ext3 filesystems.  Can I still do a live migration from the web
> interface online without risking corruption?  or do I need to shutdown
> the kvm machine?

Live migration changed in 1.4beta - works only if your VM disks are on shared storage, otherwise you need to power off them and do an offline migration. (the file system inside the VM guests is not relevant here)
Br, Martin

> Thank you for your help.  I am sure I can donate if I can get this off
> the ground.
> TonyZ

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