Recent Advances Boost System Virtualization

By Daniel Dern  |  Posted 2005-03-04

Recent Advances Boost System Virtualization

System virtualization, seen as offering enterprises and smaller organizations major benefits in application availability and server capacity management, has had several boosts in the past few weeks.

While not a product, IBMs recent release of source code for its rHype Research Hypervisor project will, among other things, help the open-source Xen virtual machine monitor project.

XenSource Inc., meanwhile, announced that it will support Intel Corp.s Virtualization Technology ("Vanderpool"), which will let multiple operating systems run concurrently on Xen Hypervisor.

And last month Virtual Iron officially unveiled its VFe data center virtualization tool at LinuxWorld in Boston.

rHype, a research project at IBM, works with a variety of processors, including x86 and Power architectures, as well as with the new IBM/Sony/Toshiba "Cell," a multicore, multithreaded processor for gaming and multimedia devices.

"IBM has made the code available to its Research Hypervisor and has previously sent a message to the Xen community stating its intent to contribute some of the skills/experience behind its Secure Hypervisor [sHype] to Xen," said Jonathon Eunice, principal analyst at Illuminata Inc.

"These moves are part and parcel of the lets all get focused on supporting Xen push weve seen lately," Eunice said. "Most of the key industry players, including the leading Linux OEMs [Hewlett-Packard Co. and IBM] and the leading Linux distributors [Red Hat Inc. and Novell Inc.], have selected Xen as the open-source virtualization project theyll focus on. "This focus on Xen comes at the expense of projects that could have received similar endorsements and contributions, such as UML, VServers and coLinux. "But in general wed call that focus a good thing," he said.

"IBM is the acknowledged master of virtualization technology, going back to CP67," said Eunice. "They were working out these issues more than 35 years ago! I think bringing their IP and understanding of the performance, availability and security issues involved to bear can only help Xen mature."

Making rHype—which, he pointed out, is not production code—"is classic strategy," Eunice said. "You dont want to necessarily put your production code into open source. You want to hold some back, you have to be careful you arent giving away someone elses code ... and a lot of production code is ugly because it supports a lot of different things in a lot of practical ways. rHype is elegant, clean, newer code, with new functions that have yet to get burned into production yet."

IBM has other, related hypervisor efforts: Power Hypervisor, a commercial hypervisor for its new Power5-based servers, and sHype, a secure hypervisor research project.

"We welcome the open-source release of the rHype code base," said Ian Pratt, senior lecturer at the University of Cambridge Computer Laboratory leader and chief architect of the Xen project, and co-founder of XenSource.

Xen is an open-source virtual machine manager, a.k.a. "hypervisor" ("hypervisor" is a term being applied to many of these virtualization management tools). Xen uses "paravirtualization," which currently requires modifications to an operating system for it to be used as a guest OS.

"Xens "paravirtualization" approach admits that it needs the guest OSes help," said Eunice. "Guest OSes must be modified to call the hypervisor when they need certain low-level resources or configuration changes. This works fine for Linux and open source, but isnt going to bring Windows, NetWare or even older versions of Linux into the virtual environment."

However, earlier this week, XenSource announced it plans to incorporate technology contributions from Intel into Release 3.0 of the Xen hypervisor.

"Intels recently announced Virtualization Technology extensions to the their x86 CPU family will mean that Xen will be able to run unmodified versions of Windows on suitably equipped systems," said Pratt. "[Advanced Micro Devices Inc.] has announced they are working on similar technology, and Xen will incorporate such support in due course." The Intel Virtual Technology is expected to enable unmodified OSes to run on Xen, albeit not quite as fast as ones that have been modified.

In addition, said Pratt, "having access to this code will significantly assist the port of Xen to the Power architecture."

According to XenSource, Xen 3.0 is targeted for availability in the third quarter of this year and will include support for 64-bit processors and Symmetric Multi-Processor (SMP) guest operating systems.

Next Page: Virtualization coming of age.

Virtualization Coming of Age

Virtualization creates a logical abstraction of the physical computer hardware, allowing a single computer to appear and function as many virtual machines, each having its own view of the systems resources. Some virtualization products, notably Virtual Irons VFe, aggregate multiple machines into the appearance of one.

Leading players in the virtualization arena currently include VMware, Microsofts Virtual PC, formerly Connectix; Sun Microsystems Inc.s Solaris Containers, formerly N1 Grid Containers (for OS sharing, not hardware sharing); and open-source initiatives including Xen.

The various virtualization and partitioning technologies have similarities—and differences.

"IBMs rHype creates partitions, subdivisions of a machine," said Illuminatas Eunice. "In a sense, its a very lightweight virtual machine ... much closer to the LPARS [Logical Partitions] in IBMs pSeries products."

The difference, Eunice said, is that "while virtual machines tend to abstract a lot of the I/O elements of a system, partitions do much less of that. For example, in VMware, if you want to copy a VM from system to system, you can do so, and copy all of the files with it, the local storage files. That is harder to do in partitioning products, its not built in. So partitions tend to be about slicing up CPU time or memory, not about building an entire envelope to contain running applications."

Some, like Microsofts, run only on Windows, and some, like Suns Containers, will only create more instances of a systems operating system, rather than allow a range of operating systems and versions.

One of the new players, VFe, from Virtual Iron, is a data center virtualization solution that can aggregate multiple devices as well as divide individual ones. The experience of company founders includes work on Digital Equipment Corp.s VAX clusters and storage virtualization technology, as well as at Thinking Machines Inc., so the "carve many from one, combine many into one" approaches make perfect sense.

"The problem that clusters and grids have is that they have to be made application-aware," said Alex Vasilevsky co-founder and chief scientist at Virtual Iron. "VFe hides the cluster and presents one single computer that consists of virtual processors, so you dont need to make them cluster- or grid-aware, or buy clustered file systems."

There are even application-level virtualization tools, like Softricitys SoftGrid. For example, according to Raghu Raghuram, senior director of strategy and market development at VMware, which pioneered virtualization on x86 platforms seven years ago, "If you deploy an application on your Windows desktop, it makes changes to your registry. A second application may need to make competing changes. Softricity solves that by making a virtual registry at Windows level."

For enterprises, whats significant is not so much any one of the recent announcements as the rapid speed and broad contribution into open virtualization, said Eunice. "Whether its Xen or rHype or Intels Vanderpool or AMDs Pacifica, everyone is focusing on getting virtualization to the masses."

And companies large and small can benefit from virtualization of their servers and data centers, Eunice said. "The smaller the server, the worse the problems are for fault isolation and security breaches." Coming to the rescue: "Theres a whole class of mainframe technologies that will start to become available in the next two years. Virtualization will be a part of the solution ... youll be able to do partitions, virtual machines, and get good quality of isolation out of the box, and probably for a fairly low price as well." The result: "Better reliability, from a fault, failure and security point of view," predicted Eunice. "And much better utilization."

"Virtualization is a powerful mechanism," said VMwares Raghuram. "Today, you can use it to turn your data center into one flexible compute pool. Another use is for more cost-effective disaster recovery. Because virtualization [with VMware] takes the applications and operating system, and abstracts them from the hardware, you can bring up a VM instantly, and you dont have to keep your primary and secondary hardware identical, which saves in operational costs."

While consolidating servers brings benefits, "that was for a single box," said Nigel Dessau, vice president of Virtualization Solutions at IBM. "The question now is, how to do it across the enterprise."

Next Page: Four stages of virtualization.

Four Stages of

Virtualization ">

Dessau reports seeing companies approach virtualization in four stages.

"The first stage is simplification—virtualizing similar resources, consolidating servers or storage devices, to manage them as a single thing." According to Dessau, this represents about 90 percent of the virtualization market today.

Second, Dessau said, is virtualizing at the application level, which may involve combining unlike resources, to be managed as one, e.g. using a tool like IBMs Dynamic Infrastructure (IDI) for mySAP Business Suite. "Those customers often end up with islands of virtualization."

Third is doing virtualization across the whole enterprise. Rather than connecting islands of virtualization, suggested Dessau, "the answer seems to be rethinking the whole infrastructure."

And lastly, accessing external virtualized resources, such as processing utilities.

"Start by simplifying your server environment," Dessau advised. "Make sure the complexity is taken out of what youre doing today."

Yet to be addressed, he added, is how system virtualization will change the culture of IT, the way that storage virtualization has already begun to.

Daniel P. Dern is a freelance technology writer based in Newton Centre, Mass.)

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