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Foundation features of RHEL6

In the presentationPDF, Red Hat explains how RHEL6 is to become an optimised virtualisation guest and host, as well as offering extended management functions, improved power management and further RAS (Reliability, Availability, Serviceability) features. The developers also mentioned new desktop features, extended hardware support and improved scalability to ensure that RHEL can be used on current as well as future systems.

From page ten onwards, the 46-page presentation goes into detail, explaining the most important improvements and new features of RHEL6 one by one. Among them are the cgroups, which allow users to put limits on such resources as the CPU, memory, network bandwidth and disk I/O. For example, an important database application or virtual machine can be allocated 90% of the hard disk's data throughput, and the remaining 10% can be assigned to a parallel test instance – this prevents the latter from reducing the overall performance of important services.

Zoom New power management functions are designed to considerably reduce some systems' power consumption during periods of inactivity.
The presentation also provides details about the new version's improved power management – comparative measurements of RHEL 5.4, RHEL 5.5 and the beta of RHEL 6 are designed to demonstrate the degree to which such power saving measures as the tickless kernel, ASPM, ALPM, Relatime and other features which have all been introduced with RHEL6, can reduce the power requirements of inactive kernels. The summary also highlights improvements in the storage area such as the discard support, which is important because it informs SSDs about newly available storage areas via ATA trim and also simplifies garbage collection, which can improve performance. RHEL6 also uses storage topology information to correctly align partitions, which enhanced support for components such as RAIDs and hard disks with 4-KByte sectors. RHEL6 will also support UEFI, an important feature for storage devices with capacities beyond 2 Terabytes.

Zoom Brian Stevens' keynote explained some of the most important new features of RHEL6 - such as support of up to 4096 processors.
Various further functions are designed to improve scalability to ensure that RHEL will run both on current and on future very large servers. Most of them have already been introduced into the main development branch of Linux in recent years and some of them have been co-developed by Red Hat employees. The optimisations enable RHEL6 to handle up to 4096 processor cores instead of the 64 or 192 available in RHEL5; the maximum storage capacity is increased from one Terabyte to eight. Red Hat says it has improved performance in terms of virtualisation, and guests are now said to perform almost as well as they would without virtualisation.

In his presentation, and in talking to heise open, Tim Burke highlighted the support of Svirt – which is only marginally discussed in the presentation – as an important feature. Requested by many corporate customers, the SELinux-based security feature is designed to make life harder for attackers who try to break out of a guest system. Burke also mentioned that the SELinux security framework, which is notoriously considered too complex by many desktop users who tend to disable it as a result, is active in the majority of corporate configurations. RHEL6 can also be run as a guest system under RHEL5 to give customers a simple way of testing and migrating to the new RHEL6 version.


Many further presentations directly or indirectly discussed RHEL6. For example, the "Red Hat Enterprise Linux 6 Security Feature Overview"PDF presentation offered a discussion of the added security improvements, and Samba admins who use RHEL can find information about current and forthcoming improvements in "Samba in Red Hat Enterprise Linux 6, clustering and other new features"PDF.

Zoom Video recordings of the keynotes and of some of the presentations are available on the Summit's homepage.
Aside from RHEL6, the Summit's main topics included the virtualisation with RHEL and RHEV. The "V2V Moving VMware & Xen Virtual Machines to Red Hat Enterprise Virtualization / KVMPDF presentation explained the new V2V tool, which is used for importing guest systems that are based on VMware or RHEL5-Xen into RHEV; for more detail on the subject, see the video of the presentation on the "Red Hat Summit" tab on the Summit's highlights page.

Bill Burns' presentation entitled "KVM in RHEL6 "PDF described some of the advancements in the KVM area that are designed to improve RHEL6 virtualisation – as RHEV 2.3, scheduled for the second half of 2010, is to use the hypervisor of RHEL6, these same improvements will benefit the virtualisation products in the RHEV family. KVM virtualisation is also the main topic discussed in "Achieving Peak Performance from Red Hat KVM-Based Virtualization"PDF. This presentation offered further information about KVM in RHEL6 as well as practical system configuration tips for boosting performance, which also apply to RHEL5, such as using the "Deadline" I/O scheduler which is said to improve the I/O throughput in KVM virtualisation in many cases. In "Kernel Virtualization Optimizations for KVM"PDF, kernel specialist Rik van Riel described the optimisations Red Hat employees working on the kernel have made to improve KVM performance. A joint presentation by Microsoft and Red Hat employees entitled "Red Hat/Microsoft Virtualization Collaboration and Running Red Hat Enterprise Linux on Microsoft Hyper-V"PDF deals with some aspects of using RHEL on Windows servers with Hyper-V.

Zoom The RHEV 3.0 Manager, which is scheduled for 2011, is no longer said to depend on Windows.
Background information about the various RHEV variants, as well as practical examples, is available in the presentations entitled "Red Hat Enterprise Virtualization Architecture"PDF and "Red Hat Enterprise Virtualization Best Practices & Advanced Use"PDF. The first presentation also discusses the Java port of the RHEV Manager software, which, in the long run, will allow RHEV-M to run independently of a Windows server; the Java software is already planned to be used in version 2.3 but is only scheduled to become fully operational under Linux with version 3.0, which is expected in 2011.

The second presentation deals with such topics as high availability with RHEV and describes how various customers use Red Hat's virtualisation products. IBM is said to extensively use the RHEV-H hypervisor and considers SELinux highly important. Voddler uses RHEV in its streaming services, which indicates that the problem of I/O performance in guest systems, often poor when the virtualisation hype began a few years ago, no longer limits its uses.

Next: Background information and tips, keynotes and outlook

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