Xen.org announced release 4.0 of its widely deployed, open source Xen virtualization hypervisor. The Linux-ready Xen 4.0 is touted for its enhanced network card support, performance and scalability gains, memory and security optimizations, fault tolerance features and improved Intel and AMD processor support.

We last checked in with the Xen last May, when Xen.org released Xen 3.4. The release offered device pass-through improvements using Xen Client Initiative (XCI) technology, enhanced integration with the Microsoft Hyper-V hypervisor, and improved reliability and power management, according to the project (see farther below for more background on Xen).

Xen 4.0, which is said to have involved contributions from more than 50 technology vendors, universities, and virtualization experts, was driven by the increasing demands of cloud computing, says Xen.org. The new release adds memory and security optimizations that make virtualization "suitable for all workloads," says the project. Supported applications include network intensive and high performance computing (HPC) applications that "would have previously experienced compromised performance on any hypervisor," claims the project.

In a story by our sister publication eWEEK, Jeffrey Burt interviews Ian Pratt, founder and chairman of Xen.org, as saying "Now it's almost possible to say that there are no apps out there that are not good for virtualization. Now you can look at everything in the data center [as candidates for virtual machines]."

Major new features in Xen 4.0 are said to include:

• Fault tolerance — Xen 4.0 now supports live transactional synchronization of virtual machine (VM) states between physical servers as a basic component, enabling administrators to guarantee a high degree of service reliability without requiring additional software, says Xen.org.

  

• High Availability — Xen 4.0 is said to leverage the reliability, availability, and serviceability (RAS) features in new high-end processors, including the Intel Xeon 7500 and AMD Opteron 6000 "Magny-Cours" (pictured).
• Netchannel2 — Xen 4.0's NetChannel2 exploits networking card enhancements such as Smart NICs with multi-queue and SR-IOV functionality, for faster data processing, claims the organization.
• Blktap2 — High performance VM snapshots and cloning features are said to be available via a new virtual hard disk (VHD) implementation, which also lets users perform live virtual disk snapshots without stopping a VM process.
• PVOps Domain0 — The addition of formal support for the PVOps option in the Domain0 (Dom0) Linux kernel provides "access to the most recent devices supported by the Linux kernel," says Xen.org.
• Memory Enhancements — New transcendent memory and page sharing algorithms are said to enhance hypervisor memory operations.

According to Pratt, the new fault tolerant features will be particularly useful, says the eWEEK story. While the previous versions of Xen enabled businesses to migrate VMs from one physical server to another for planned outages, unplanned outages typically led to problems, Pratt told eWEEK.

The new fault-tolerant feature enables a VM on one physical machine to be mirrored by a VM on another physical server, he said. Should one physical server go down, then the backup VM would continue running without interruption.

"The new thing here is to … have the ability to keep a second [VM] in sync," Pratt told Burt. "[In the event of an outage], everything just seamlessly switches over to the other machine."

Eight-core version of Intel's Xeon 7500 "Nehalem EX"

Pratt was also said to have touted Xen 4.0's support for the RAS (reliability, availability, and serviceability) features in Intel's Xeon 7500 "Nehalem EX" and AMD's Opteron 6000 "Magny-Cours"processors. Announced around the same time in late March, the processors are billed as the chipmakers' highest-performing x86 processors. Xen 4.0 now supports more than 20 RAS features inside the Xeon 7500 chips that until now were normally found in RISC processors, including MCA Recovery error correction, says eWEEK.

Xen background

The Xen paravirtualization technology provides a platform for testing, deploying, and running multiple operating systems (OSes) on one isolated physical hardware resource. Xen supports Linux, Windows, FreeBSD, and NetBSD, and Linux, for which major improvements to Xen support was added with the Linux 2.6.23 release in 2007.

Among other commercial products based on Xen, Citrix offers its XenDesktop and XenServer, incorporating technology acquired by the company when it acquired hypervisor vendor XenSource in 2007. Citrix' XenDesktop3, for example, is said to enable desktops to be run remotely or locally, supports twice as many desktops per server, and includes "HDX MediaStream" technology for multimedia acceleration.

Xen is increasingly used to consolidate servers, as well as to lower hardware and maintenance costs and minimize downtime. Vendors such as IBM, Sun, HP, RedHat, and Novell are integrating Xen into their Linux servers.

Testimonials

Testimonials provided for Xen 4.0 from Xen Advisory Board members, include the following, omitting additional quotes from Fujitsu, Oracle, and VA Linux Japan:

• Stated Simon Crosby, CTO, Datacenter and Cloud Division, Citrix Systems, "The new advancements in Xen 4.0 will bring cloud and virtualization to new levels, and Citrix is dedicated to applying them across our entire stack – from desktop virtualization to cloud computing."
• Stated Doug Fisher, VP of the Software and Services Group and GM of the Systems Software Division, Intel Corp., "By taking advantage of advanced features in the Intel Xeon architecture to provide server high availability, power efficiency and hardware assisted virtualization; delivering SRIOV to improve both bare metal network and storage performance; and supporting multiple cores to achieve increased virtual machine density, we see Xen 4.0 being an outstanding release for the Xen community."
• Stated Carlos Montero-Luque, VP of Business and Product Management, Novell, "As the first enterprise Linux vendor to ship and support the Xen hypervisor, Novell is pleased to bring Xen 4.0 to market within SUSE Linux Enterprise Server. We look forward to shipping Xen 4.0 in SUSE Linux Enterprise Server 11 Service Pack 1 this quarter."

Availability

Xen 4.0 is available for immediate download from the Xen community site, here.

A Xen Summit North America event will be held on April 28-29, at AMD headquarters in Sunnyvale, Calif., says Xen.org. Registration is $235 for the two-day event. More information may be found here.

The eWEEK story on Xen 4.0 may be found here.

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