Re: [CentOS-virt] XEN and RH 6

On 11/10/2009 03:57 PM, Grant McWilliams wrote:

I've been wondering about the definition of PV in the context of
KVM/Xen.
In the Linux on Linux case for Xen PV practically means that in the HVM
case I have to access block devices using /dev/hda while in the PV
case I
can use the faster /dev/xvda. When using KVM which apparently only
supports
HVM I can still install a guest using the virtio drivers which seem
to do
the same as the paravirtualized devices on Xen.

So what is the KVM+virtio case if not paravirtualization?

Regards,
   Dennis
__________

All of it except for that! Your VM isn't just a process accessing a disk. With KVM they've attacked the most commond devices - network and disk and offered paravirtualized devices. This doesn't concern me as the speed has proven to be good although in mysqlbench Xen still leads by quite a bit. I'm concerned about everything else. With 41 interactive VMs I worry about how fast the hypervisor can switch focus, the cpu utilization of each etc..

I get that but if the line is becoming this blurry (with KVM apparently beeing "somewhat" paravirtualized) does it make sense anymore to distinguish between HVM/PV?

Regards, Dennis