Linux Startup Moves Desktop Windows to the Data Center

Qumranet, the company behind one of the hottest Linux kernel features, is scheduled to announce its first product, a new desktop virtualization system, offering today at the DEMOfall conference in San Diego. Qumranet's Solid ICE product moves desktop users' Linux or Microsoft Windows installs onto virtual machines in the data center, allowing the users to run their applications and OS of choice from thin clients or from Windows or Linux PC clients. Unlike VMWare's ESX server, the Solid ICE server runs on a host with a standard Linux distribution from Red Hat, Novell, or Canonical.

The company already has five Fortune 1000 customers participating in an early adopter program, says John-Marc Clark, the company's VP of Marketing.

Qumranet offers a physical to virtual (P2V) tool for converting a customer's physical OS images to virtual machine templates, says Rami Tamir, the company's President, VP of R&D, and co-founder. The company offers a remote desktop protocol it calls SPICE, which Tamir says is suitable for use over a LAN and supports high-bandwidth uses such as bidirectional audio and video. Solid ICE also supports RDP for lower-bandwidth links, but Tamir recommends "remote presence" --moving a running guest machine from its original server to one closer to the user. Solid ICE does not have support for offline use independent of the server.

The number of users per server is limited by available memory, Tamir says. "we are typically quoting from 5 to 10 users per core," he says, but the number could go up or down depending on applications. Solid ICE "oversubscribes" the server's memory by 40 percent, so a server with 10GB of RAM could accomodate 14GB of guests. Qumranet's management interface allows for guest systems to migrate transparently from host to host to balance the load.

In the Solid ICE client interface, users can browse a selection of virtual machines and start the ones with the applications they need. Client systems may be Linux or Microsoft Windows PCs, thin clients, or, for customers who want to convert old PCs to lightweight systems, Linux machines running Qumranet's "miniOS." miniOS is just enough to get the Solid ICE session started and let the user launch his or her virtual system.

Based on the results of the early access program, Clark says he anticipates that a common use of Qumranet's technology will be to faciliate upgrades and migrations. Companies will be able to keep old OS and application installs around if needed in a transition. And the virtual machine images are stored in a compressed format that encourages users to keep several, Tamir says. "Keeping an old desktop costs you nothing -- you just keep a diff from a template," he says.

The user interface simulates the controls of a desktop PC, so a user can power off a virtual machine or leave it running. A helpdesk worker can "clone" a problem system to test a fix while the user continues to work on the original, or view or take over a user's session.

Solid ICE supports Microsoft's Windows Vista, Windows XP, Windows 2000, and Windows Server 2003 as guests, along with Linux.

Stealth product, but open source fanfare

Although KVM entered the mainstream Linux kernel with version 2.6.20 in February, Qumranet has backported KVM to run on the earlier kernels on Red Hat Enterprise Linux and SUSE Linux Enterprise Server. Besides those two Linux distributions, Qumranet also supports Canonical Ltd.'s Ubuntu Linux as a server platform.

KVM requires Intel VT or AMD-V virtualization support in the hardware on the host system, but Qumranet's co-founder and VP of R&D says he doesn't see that as a problem. "Going forward all new servers are going to be VT," he says. However, IBM researchers are working on a version of KVM that will not require hardware virtualization support, he adds.

In the months before the product announcement, KVM built a fan base among kernel developers, getting into the kernel before the older and better-known Xen.

Kernel developer and author Jonathan Corbet wrote, "The speed with which the KVM developers have been able to add relatively advanced features is impressive; equally impressive is just how simple the code which implements live migration is."

At LinuxWorld Conference and Expo in San Francisco, kernel maintainer Andrew Morton also had a good word for KVM. "It looked like the guys had been working in kernel land for years," he said in a conference kickoff talk on kernel development.

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