Xen Opens Up a Little More

by Sean Michael Kerner

The latest version of the Xen hypervisor offers new API support, improved 64-bit paravirtualization and the ability to move virtual machines on the fly.

The Xen open source project released a new version of the Xen hypervisor this week with a little help from Intel, IBM, Novell, VA Linux (Japan), HP, Fujitsu, SGI, Red Hat, AMD, Sun, Unisys and the National Security Agency.

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Xen 3.1 extends the open source virtualization technology with new API support, improved 64-bit paravirtualization and a feature for moving virtual machines (VMs) on the fly. Xen is an included component in a number of Linux distributions, including Red Hat, Novell and Ubuntu.

The open source effort has benefited greatly from community contributions and is considered a viable competitor to industry leader VMware.

"For server workloads, Xen's core hypervisor functionality now meets or beats VMware ESX in pretty much all areas, both features and performance," Ian Pratt, leader of the Xen project and founder of XenSource, told internetnews.com.

One of the key new features in Xen 3.1 is Live Relocation. Live Relocation is the ability to move a running virtual machine from one physical server to another with virtually no interruption to the operating system and applications running in it (just a couple of hundred milliseconds during the final switchover).

"It basically works by synchronizing the memory image of the running virtual machine between the source and destination hosts, and then migrating the final CPU state etc," Pratt said. "VMware calls this feature 'VMotion.'"

While Xen has benefited greatly from the contributions of its community, with the XenAPI, the hypervisor will become even more extensible.

"The XenAPI can control pretty much all aspects of Xen," Pratt said. "You can provision new VMs, perform lifecycle management operations, and live relocate VMs, etc."

Though Xen 3.1 is now available, it will take a bit more time until the new hypervisor finds its way into the XenSource commercial offering.

XenSource is the commercial backer behind Xen and offers additional technology and support offerings on top of the open source base. The latest XenEnterprise offering from XenSource is actually numbered XenEnterprise 3.2.

"Although there is a substantial user and developer community that tests Xen open source release candidates, it does take further soak testing and certification to 'harden' an open source Xen release into the quality required for XenEnterprise," Pratt explained.

"XenSource has invested heavily in verification lab automation, so the process usually takes just two to three months."

Moving beyond the 3.1 release, Pratt has his eye on what he referred to as a number of interesting new hardware features arriving soon in CPUs, chipsets and network cards that are very useful for virtualization. His plan is to make sure Xen has great support for these features ahead of them shipping.

"Laptops and desktops are among the most interesting areas for focus going forward," Pratt said. "We want to make sure we do a good job of 3-D graphics virtualization, power management, USB, etc."

This article was originally published on interentnews.

This article was originally published on Thursday May 24th 2007
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