The Linux Foundation releases Xen 4.3 virtualization manager

The Xen hypervisor has just had a new release under its new management, The Linux Foundation.

The Linux Foundation used to be just about, well, Linux. Now, it also manages an open software defined network alliance, OpenDaylight, and the open-source Xen virtualization manager. On July 9th, the first fruit of these new efforts arrived: Xen 4.3.


Xen, formerly maintained by Citrix, is used by numerous well-known businesses that include AMD, Google, Intel, and Oracle. It is used both as a virtualization platform and as the backbone for massive cloud deployments by such companies as Amazon Web Services (AWS) and Rackspace's OpenStack-based cloud.

This new release, which is licensed under the GPLv2, includes the following new capabilities and improvements: 

ARM server support: ARM servers support is incorporated as a Technology Preview. The Xen Project community, working with ARM server hardware vendors including Calxeda, has validated the Xen ARM port on ARMv7 and ARMv8 platforms. 

Performance and scalability enhancements: The new Non-Uniform Memory Access (NUMA) scheduler will provide significant performance improvements on NUMA hardware. 

Specifically Xen will now support from 5TBs to 16TBs of RAM. A tool stack bottleneck limitation to 300 virtual CPUs was removed and Xen Project has already been tested on up to 750 virtual CPUs. Finally, with block protocol scalability, users will see significant improvement in read/write performance and throughput with more than six guests on a single host. All of this means that Xen will support clouds better than ever. 

Improved security: The Xen Project’s virtual Trusted Platform Module (vTPM) subsystem has been extended to enable guest operating systems to more easily interact with it. Each guest now has access to unique emulated software but can only access keys that are released by a special vTPM manager domain. 

In addition, the scope of the XSM/Flask security subsystem has been extended to cover both privileged and unprivileged APIs. This will enable developers and server administrators to improve Xen virtual machine (VM) security by breaking down the control domain into smaller, compartmentalized units.

Improved QEMU integration: Xen Project now works with upstream QEMU, a hosted virtual machine monitor. This will make it easier for Linux distros to work with Xen. 

SDN integration: The new Xen includes a technology preview of Open vSwitch. vSwitch, in turn, is used in OpenDaylight for SDN integration. 

Better Power efficiency: Finally, Xen's infrastructure now uses the MWAIT extension for all the high-end Intel chips, from Sandy Bridge on, which supports it. This will improve Xen’s power efficiency.

“Virtualization is important to Linux and the open source community and the Xen Project is helping companies realize new levels of scalability and efficiency in areas such as cloud computing,” said Mike Woster, chief operating officer and vice president of The Linux Foundation in a statement. “With the latest release of Xen Project, organizations can advance their cloud computing strategies to deliver on customer expectations for their enterprise environments.”

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