IT Week: Is virtualisation the cure for all datacentre problems?
Rich Green: Virtualisation is not without limitations and risks. There is increased management complexity, for example, because you now have 10 servers with hundreds of operating systems [OSs]. A hypervisor does not remove the need to manage either the underlying hardware or the OS. There are also performance overhead limits in terms of the computer resources that hypervisors consume, though most enterprises are not worrying about this yet.

What are Sun’s plans for server virtualisation?
Sun’s forthcoming xVM platform is a set of products that will focus on systems and network management techniques, both runtime and the tools to manage virtualised environments. We do not think that having one without the other is compelling [for enterprise buyers]. The xVM Server [a preview of which is due on 1 January] will be Sun’s implementation of a type 1 hypervisor, essentially a platform that runs directly on the metal to provide a host environment for one or multiple guest OSs, including Microsoft Windows. The xVM Ops Center [due 1 January] is designed to provision and manage both virtual and physical hardware, and the guest OSs running on top of them. It allows us to manage the hypervisor itself, and deal with issues like live migration and dynamic workload balancing.

How does integrating the Sun hypervisor with Solaris containers help improve system performance?
Other approaches use a sort of N+1 resource consumption model, whereby one host and N guests are each providing for full workload demands for the system ­ essentially small versions of the OS running on the system. In the container model, there is no N and no N+1 but just one OS, which raises workloads and means more apps are running on the system. There is no doubt that running virtualisation can lead to performance trade-offs, but by running only one instance of the OS, those performance trade-offs are not significant in most cases.

Sun is relatively late to the hypervisor party, why has it chosen to make its entrance now?
The market is not young, but it is still quite basic. The completion of Sun’s Cluster File System (CFS) and Crossbow [networking virtualisation] technologies allows us to deliver a radically different hypervisor, and we spent a lot of time working with Intel, AMD and Microsoft to make sure we had all the right ingredients for commercially attractive hypervisor offerings.

Will Sun provide a stripped-down OEM version of xVM, and how much will xVM cost?
We may very well do, but we are not ready to announce that today. What I can say is xVM will offer significantly better value than what you can get today.

About Rich Green
Rich Green is the operational leader of Sun's software division, overseeing Solaris, Java Enterprise and Java Studio.
Prior to rejoining Sun in May 2006, he spent two years at system virtualization specialist Cassatt.
His previous 14 years at Sun saw Green lead the Java development and serve as vice president and general manager of the Solaris products organization.

‹ www.sun.com/datacenter/consolidation/virtualization