I finally got around to testing KVM. I usually use VirtualBox. The test was very easy. Everything worked. The only real difficulty I had was getting an .iso to boot. It turns out there is a “connect” button I did not notice far to the right in the configuration widget. My eyes? User interface? I don’t know but it turns out to be every bit as easy to use the GUI for KVM as VirtualBox. I even ran KVM inside VirtualBox. Everything worked.
apt-get install qemu-kvm virt-manager in Squeeze
adduser me libvirt
Then I loaded the driver (avoiding a reboot) and ran virt-manager and it was very similar to VirtualBox from there.
From now on I will prefer KVM over VirtualBox thanks to the shenanigans of Oracle v Google etc. If KVM is solid enough for RedHat, it is solid enough for me.
“KVM is included in the mainline linux kernel since 2.6.20 and is stable and fast for most workloads.” There are technical reasons to use KVM as well. Now being in the Linux kernel means it should be continually available. I have no confidence that Oracle will be smooth with VirtualBox. Parts of VB (“extensions”) are already non-free (“free for personal use”…).
see TheVarGuy for a review/comparison earlier. My first experience with KVM was much better than his but that may be because KVM was evolving rapidly back then. Phoronix did some benchmarking with peculiar results (some virtualization was faster than native… clock error? caching?) but it is clear that KVM and VB give similar performance in many cases.