Remember when the Linux Foundation used to be just about the Linux operating system? That's no longer the case. Back in April, Citrix announced it was donating its open source Xen hypervisor to the Linux Foundation group. In doing so, Citrix may have given Xen virtualization a new lease on life.
Mike Woster, COO and vice president at the Linux Foundation, said, "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."
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Citrix decided to give up control of the Xen hypervisor to a more vendor-neutral environment much like it did with the company's recent donation of another project, CloudStack, to the Apache Foundation. With similar reasons in mind, Citrix made this latest move in the hopes of attracting a more diverse set of contributors to the Xen hypervisor code in order to better compete with the likes of VMware vSphere, Microsoft Hyper-V, and the open source KVM virtualization platform.
At the time of the transfer, the Linux Foundation said it would support continued development and maintenance of Xen, and it established the collaborative project aptly called the Xen Project. With the move to the Linux Foundation, companies such as Amazon Web Services, AMD, CA Technologies, Cisco, Google, Intel, Oracle, Samsung, and Verizon all pledged support for the project.
Fast-forward to last week and this group is ready to make good on its promise with a new release of the Xen hypervisor: Xen Version 4.3.
According to the group, Xen 4.3 is the work of just over nine months of development, with 1,362 changesets containing changes to over 136,128 lines of code -- made by 90 individuals from 27 different organizations and 25 unaffiliated individual developers. Citrix still contributed the largest percentage of the changeset count at 41 percent, but other companies have stepped up to the plate as well such as Suse Linux picking up 23 percent, Intel providing 6 percnet, and the U.S. National Security Agency doing another 5 percent.
The new release is licensed under GPLv2 and includes a number of new capabilities and improvements, such as the following:
- Performance and scalability enhancements: The new Non-Uniform Memory Access (NUMA) scheduler will provide significant performance improvements on NUMA hardware. Xen 4.3 also boosts physical memory support on hosts from 5TB to 16TB of RAM. A tool stack bottleneck limitation of 300 virtual CPUs was removed, and tests now reach upward of 750 virtual CPUs. With block protocol scalability, users will see an improvement in read/write performance and throughput with more than six guests on a single host.
- Improved QEMU integration: Earlier releases of Xen had been using a fork of the QEMU hardware emulator, but the Xen Project has switched the default QEMU to QEMU-XEN, which is based on the release of the upstream QEMU project. This will make it easier for Linux operating system distributors to integrate Xen into their distros.
- Software-defined networking (SDN) integration: Xen includes a technology preview of the Open vSwitch technology created by Nicira, now part of VMware. The Open vSwitch is an open source virtual switch technology used as a bridging mechanism to replace older virtual interface code that was originally part of Xen. This is expected to be a fully supported feature in the Xen 4.4 release.
- Better power efficiency: Xen now uses the MWAIT extension of all the modern Intel processors that support it, from Sandy Bridge on. This will improve Xen's power efficiency.