Original URL: http://www.theregister.co.uk/2010/02/23/red_hat_5_5_review/

RHEL 5.5 - extra lube for your KVMs

CentOS for grown ups

By Scott Gilbertson

Posted in Operating Systems, 23rd February 2010 23:41 GMT

Review Red Hat's Enterprise Linux (RHEL) version 5.5 has reached the beta stage with downloads available for those with a subscription to the Red Hat Network.

Typically, most news involving Red Hat's familiar, free Linux distro Fedora comes from the client software - such as GNOME updates and other desktop tools. But with the new RHEL, the big news lies with improvements to kernel-level software.

The RHEL 5.5 beta brings a slew of hardware improvements, including support of IBM's new Power7 chips, which are looking like a popular platform for Linux on embedded devices. This release also brings more driver support for external devices and run-time memory allocation for virtual machines.

For a complete list of everything new and improved in RHEL, you can check out the technical notes on the Red Hat website. But what really catches the eye is the work done on the Kernel Virtual Machine (KVM).

RHEL 5.4 brought full support for the KVM hypervisor, making KVMs the primary virtualization solution. RHEL 5.5 aims to continue that trend. Chief among the new features for KVMs in this release is the better memory management and improved device interactions. As of this release KVMs will be able to use any attached PCI devices as if they were attached directly to the guest OS, rather than running as virtualized devices.

On some hardware, notably Intel machines running VT-d extensions, PCI devices can be swapped and reassigned while a virtual system is running.

RHEL 5.5 also allows you to reallocate memory while a virtual machine is running so there's no need to shut down your servers or guest operating systems just to increase or decrease the allocated RAM.

Samba also sees some love in RHEL 5.5, with improvements that should make working with Microsoft Windows 7 and Windows 2008 Server a bit smoother.

As with many features in RHEL, if you've been using recent releases of Fedora many of the latest features in RHEL may be familiar. For example, recent improvements and many much-needed bug fixes to the Anaconda system installer are also now available in RHEL 5.5.

While RHEL is probably most familiar in server setups, the desktop workstation has been updated as well with the latest version of the GNOME desktop and all usua,l accompaniments, including the latest version of OpenOffice.org. Plus there's support for Microsoft's Office 2007 Office Open XML (OOXML) file formats.

Those that do use RHEL on the desktop will be happy to hear that WIFi support is a big part of the coming 5.5 release. There's support for Ralink rt2 drivers as well as drivers for Intel WiFi cards and the Atheros ath9k driver for the latest chips.

For those of you who don't manage datacenters' worth of RHEL server and don't want to spend the big money on an admittedly well supported desktop version, then you'll likely want to stick with CentOS, the free version of RHEL.

The bottom line

So what did I make of the RHEL 5.5 beta? I found it to be, well, quite nice. It was my first exposure to RHEL directly, though I'm familiar with CentOS, and indeed, aside from the prominent Red Hat branding, things looked and behaved much like CentOS.

Of course, CentOS isn't the only auxiliary RHEL distro (though it is the most popular). Others that will eventually benefit from this release include Scientific Linux and Oracle's Enterprise Linux.

If you'd like to upgrade CentOS or the others mentioned here now, you can grab the kernel, but you'll have to wait for some of the other new tools.

As for RHAT itself, there's not final date yet. The beta is scheduled to run through March 16, 2010, and I expect final code to be available near the end of March.

Ahead of that release, I'd say the beta provides a solid update for RHEL. The new KVM tools and additional device support will make RHEL 5.5 well worth the upgrade when the final release does arrive later this year. ®