/training/etc News

Released in September 2009, Red Hat Enterprise Linux 5.4 marks the fourth cumulative enhancement and bug fix release in Red Hat Enterprise Linux 5, and provides the foundational piece for the Red Hat Enterprise Virtualization portfolio.

Red Hat Enterprise Linux 5.4 commercially releases the next generation of virtualization technology through incorporation of Kernel-based, Virtual Machine (KVM) technology with the operating system providing the next step in delivery of the Red Hat Enterprise Virtualization portfolio. KVM is integrated
into the Linux kernel and takes advantage of all of the hardware and software support already available for Red Hat Enterprise Linux 5. Designed to leverage the latest advances in x86 virtualization support from Intel and AMD, this next-generation virtualization technology reduces the overall overhead of virtualization.

KVM is a loadable module in the Red Hat Enterprise Linux kernel and benefits from all the features and the stability of the kernel, such as process scheduling and NUMA support. KVM leverages the presence of virtualization-enabled CPU architectures, like Intel VT and AMD-V, to deliver remarkable performance, security and scalability. KVM itself consists of two major components:

A device driver managing virtualization hardware
A user-space component for emulating PC hardware

In addition to the introduction of a new hypervisor, Red Hat Enterprise Linux 5 adds new virtualization support features such as hugepages and improved scaling for hypervisors.

Hugepages
Red Hat Enterprise Linux has traditionally supported a fixed hugepage size of 2MB to improve performance of applications that are memory intensive such as databases and virtual machines. This release enables 1 GB hugepages in addition to 2MB hugepages on the x86_64 platforms that
have GB hugepage support.

Scaling
Red Hat continues to test the limits of Red Hat Enterprise Linux with commercially available hardware. While maintaining the virtual machine limits, the Red Hat Enterprise Linux 5 hypervisor has shown increased scalability from 126 cpus to 192 cpus. For production use, please consult the hardware catalog for a current list of certified systems and limits.

Development continues on the Xen-based virtualization technology, which will be supported throughout the
Red Hat Enterprise Linux 5 release cycle until at least 2014. Libvirt, the open standard API for managing virtual machines has been extended to manage both virtualization technologies. With the inclusion of Xen, KVM, and libvirt technologies, this release simplifies the support, deployment, and certification of virtual systems.

Excerpted from "A Technical Introduction to Red Hat Enterprise Linux 5.4".

Barb Stamatakis, RHCE, has been providing
Unix/Linux training and course development for the past 16 years. She holds several industry certifications and teaches the Red Hat Linux RH033, 133, 253 and 300 courses.