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Fedora 12 Linux Tackles Virtualization

Virtualization has been a big push this year for Linux vendor Red Hat (NYSE: RHT). It's also a big area of focus for the Red Hat-sponsored Fedora Linux 12 release, which is due out next week.

The Fedora Linux distribution has been including virtualization technologies beginning with the Fedora Core 5 release in 2006 and has been steadily adding new virtualization features ever since. In Fedora 12, the open source Linux community project is adding new technology to improve virtualization memory management and performance.

The Fedora 12 release comes on the heels of Red Hat' Enterprise Virtualization (RHEV) release at the beginning of November.

"There is an immense number of virtualization improvements and features in this release," Fedora Project Leader Paul Frields told InternetNews.com. "These things will affect anyone using virtualization across the board."

On the memory management side, Fedora 12 has support for huge memory pages. Typically, x86 CPUs provide their memory allocations in 4KB page increments but with huge pages the limit is raised to 4 MB sized memory pages. Frields explained that using huge pages will make for improved virtualization performance depending on how the guest workload is configured.

How memory is allocated across virtual guests is also addressed in the Fedora 12 release. Frields noted that a key new feature is the ability of the virtualization hypervisor to understand duplicate pages across guests.

"So if, for example, you're running a host that has ten or twelve instances of the same operating system ... a large number of their memory pages might actually be duplicated across guests," Frields said. "So the system has the ability to find those pages and simply point them to one page on the host's memory. So the actual memory used drops by quite a bit."

Making changes to virtual operating systems instances has often been a manual process that has required system administrators to boot the guest operating system. That process changes in Fedora 12 with a new technology called libguestfs.

"What libguestfs does is it allows you to manipulate disk images for virtual guests without having to actually boot the systems up and interact with the operating system," Frields said. "Normally you would have to start them up and either log in or deliver some kind of script and boot the guest to run it. With libguestfs, you could script changes to make directly to the filesystems of the guests without the need to boot them at all. It makes life simpler for administrators."

While booting each individual virtual guest is a process that Fedora 12 eliminates for system changes, it on the other hand also includes improvements to how virtual guest booting works.

Fedora 12 includes the GPXE, which replaced the older Etherboot technology for remotely booting a system via PXE .

"GPXE makes for a flexible system for network booting of your virtual guests," Frields said. "Now ... when installing a virtual guest, you can literally point it at a Web repository on a local network or in the cloud, and GPXE understands how distributions place their files for installation. And it is able to boot the guest via PXE and then retrieve the pieces it needs and boot the guest."

Back when Fedora first embraced virtualization in 2006, the technology wasn't always easy to use and manage. That's no longer the case, according to Frields.

"It's a much faster process now to go from 0-60 in virtualization," Frields said. "It's practically trouble-free and almost a brainless proposition."

Fedora 12 is set for its official release on Nov. 17.