xVM isn´t just Xen

Marc Hamilton wrote about the preview of xVM, our virtualisation technology, in his blog. I wan´t to add some thoughts to it. I´ve talked with some customers about xVM in the last few days about our upcoming virtualisation. And one comment was "Hey, you´ve just ported Xen to Solaris. This isn´t a big thing". And while Xen in Opensolaris is a technical archievement, it isn´t exactly an unique selling point. So why should you use Xen on Opensolaris: Well, as usual the reason lies in the complete system called Solaris/Opensolaris.

The point behind virtualisation with Solaris is the interaction with other features integrated deeply in Solaris. For example: There is something called "Fault Management Architecture" in the operating environment. It tracks all faults in the system (for example corrected memory errors or similar early warning for imminent faults). When the amount of failures for an component reaches an threshold, the operating system deactivates it (for example, evacuates and retires a memory bank). An failing memory chip can´t destabilize the system when there are no accesses to it (okay, except really spectacular electrical faults like burning memory chips ). The point: The virtualization can leverage this function, you can even think about an auto-evacuation by live migration when the probability of an fatal error reaches a certain amoun (i wrote about this idea at several ocassions like the windows desktop virtualisation with XEN) .The same with ZFS: Think about virtual disks based on sparse provisioned emulated volumes. Get a checksum protected NTFS and circumvent the need to grow the filesystem by thin provisioning.

The advantages of xVM are systemic ones. xVM isn´t just Xen, it´s the Not the feature itself, the integration into the operating system gives the reasons to use it instead Xen on Linux or even VMware.