Originally Posted by HosterDaddy
What you say about XEN. Is it good to have XEN over KVM?
I would like to know your views.
I would say, Xen is external hypervisor; it control of the machine and divides resources among VMs. Whereas KVM is part of Linux and uses the regular Linux scheduler and memory base management. It means, KVM is much smaller and simpler to use; it is also more featureful and powerful as compare to xne; for example KVM can swap guests to disk in order to free RAM.
KVM only run on processors that supports x86 hvm whereas Xen also allows running modified operating systems on non-hvm x86 processors using a technique paravirtualization. KVM can't support paravirtualization for CPU but may support paravirtualization for device drivers to improve I/O performance.