The idea of virtualization is nothing new – the term has been used in mainframe partitioning for decades. But the innovation of using a thin layer of software called a hypervisor at the hardware level to run a number of operating systems in parallel is attracting plenty of attention because of its potential to exploit server resources like never before.
For IT managers, virtualization technology could mean money savings by getting more out of processors, I/O and disk utilization. For users, the ability to run applications available on different operating systems could mean more productivity from the same physical piece of hardware.
"Our customers are showing a definite interest in virtualization for saving money on servers, management, power -- everything," said Nick Welling, director of professional services at Littleton, Colo.-based Solutions-II Inc. The company provides storage and server sales and services.
Anecdotal evidence is backed up by research from IDC, based in Framingham, Mass., which shows that as many as 75% of the Fortune 500 companies surveyed either use virtualization technology already or expect to do so in the next year.
The latest virtualization spin, however, seems to favor a built-in hypervisor rather than a software layer that manages resources between the host and guest operating systems.
This novel design approach will play out in upcoming hardware and software products developed to optimize virtualization technology. In fact, several big-name vendors have already committed to integrating the software layer in their newest virtualization offerings:
- XenSource Inc.'s Xen 3.0 includes a hypervisor that can exploit hardware virtualization and will also support proprietary operating systems. Xen is the open source virtual machine monitor -- or hypervisor -- developed at the University of Cambridge, and the original Xen development team runs Palo Alto, Calif.-based XenSource.
- Xen 3.0 also supports 32-way SMP machines running virtualized guests, with the added capability to support hot-plugging CPUs in blade systems. Reportedly, that enables IT managers to optimally place workloads on their available server resources. Red Hat Inc. in Raleigh, N.C., and Novell Inc., headquartered in Waltham, Mass., are just two major vendors that have announced products that incorporate Xen 3.0 and its fully integrated hypervisor.
- Sun Microsystems Inc. in Santa Clara, Calif., has designed its high-end energy-efficient UltraSPARC T1 processor to incorporate hypervisor technology and present a virtualized machine environment to any guest operating system running on it. Sun developed UltraSPARC Architecture 2005 and HyperVisor API specifications to help jumpstart the porting of Linux, BSD and other operating systems, middleware and applications to the UltraSPARC T1 processor (formerly known as Niagara) as part of its OpenSPARC Initiative.
- VMware Inc. in Palo Alto, Calif., announced availability and pricing this month for its next-generation ESX Server 3 and its VirtualCenter 2 platform. ESX Server uses a "bare-metal" architecture that inserts the hypervisor layer between the x86 server hardware and virtual machines.
Microsoft recently disclosed plans to ship advanced new hypervisor virtualization software optimized for Windows, code-named Viridian, within 180 days of the release to manufacturing in a later version of its Longhorn Server, which is expected sometime in 2007.
While Microsoft labors away at its next-generation server, some have questioned whether including a hypervisor layer that tightens security and permits low-overhead operation of multiple OSes may be difficult -- or maybe even impossible -- for the software company to pull off because of Windows' monolithic design.
"Windows has historically tended to be a monolithic operating system," said Haff. But in Windows Longhorn, he said Microsoft is taking a different approach and plans to integrate a hypervisor directly into Release 2.
Specifically, Microsoft has worked with chip makers to design its hypervisor from the ground up to use the AMD-V and Intel-VT virtualization assists, said Mike Neil, product unit manager for Microsoft's virtual machine technology. "By keeping our hypervisor very thin and not allowing any outside code to run within the higher privilege level of the hypervisor, we can produce a very secure foundation for our trusted computing base," he said.
Aside from improved security, cost is another big reason that IT managers should take a close look at hypervisor technology, Neil said. Reductions in operational costs typically pay for any expenses in doing consolidation. Fewer machines mean less floor space is used and there are lower maintenance costs and lower power and cooling costs, which all reduce the customers operating costs, he said.
"By using the core role technology in Windows Server Longhorn, we can reduce the overall footprint of the parent partition, which reduces the maintenance costs associated with the system," Neil said.
Some hardware upgrades will be required to take advantage of hypervisor technology, but Haff said that those costs should not stop users from adopting it. Another plus for virtualization is that users don't need to wait for a hypervisor from Microsoft to run Windows. "They can implement virtualization today with tools that are available from companies like VMware," he said.