Review The first major update for Red Hat Enterprise Linux in more than three years hit last month, and judging by the traffic that took down Red Hat's download servers, it's long over due.
RHEL 5 came out in March 2007 with the Linux 2.6.18 kernel and while incremental updates have added kernel updates and new features, it's showing its age.
Of course, the whole point of running an enterprise distro like RHEL is that it isn't Ubuntu or Fedora, and it doesn't completely change all the rules every six months.
Still, there's a balance to be had, and even by enterprise standards RHEL 6 is a long time coming. But the RHEL 6 beta is here and the good news is that there's plenty to love.
For RHEL 6, Red Hat is using a Fedora development release based on the Linux 2.6.32 kernel - technically, it's a hybrid of several recent kernels. Red Hat engineers have hardened the Fedora base and added quite a few features - with a strong emphasis on virtualization.
One of the main goals for RHEL 6 was to make managing virtual servers as easy as managing physical machines, which means the bulk of the new software features are found in KVM. It also means that Xen is gone, though that's hardly surprising since Red Hat purchased Qumranet - creators of KVM - back in 2008.
A wide selection of disk formatting options include ext4
RHEL 6 builds on the KVM-based virtualization found in RHEL 5.5 and earlier releases, adding a number of performance and hardware support upgrades.
Also new for virtual guests is the SELinux sandbox feature that allows guest machines to run in isolated environments. The new sandbox features can be applied to just about any untrusted code you'd like to execute, but it's particularly handy with virtual machines.
Other improvements in the beta include changes to the way RHEL 6 handles multi-core chips. In theory, RHEL could use 64,000 cores in a single system image. Along with the better multi-core support comes the same support for new chip architectures that we saw in RHEL 5.5, including Intel's Xeon 5600 and 7500 and the Power7 from IBM.
Another big change in the RHEL 6 beta is the wide selection of disk formatting options, including ext4. You know a Linux feature has arrived when it makes its way to the conservative enterprise releases like RHEL and such is the case with ext4 file system, which is now the default filesystem format in RHEL 6. In addition to ext4, the XFS filesystem is now supported.
What ever you want
As with previous versions of RHEL, the Anaconda installer will offer you a number of pre-configured sets of software packages depending on your needs. You can choose from the basic server configuration, web server packages, the desktop setup (GNOME by default), what RHEL calls a "software development workstation", or the bare essentials available in the "minimal" option. There is also an option to customize your installation further, selecting individual packages.
For testing purposes, I started with the basic GNOME desktop package, adding the server platform, along with common tools like MySQL, PostgreSQL, FTP server and e-mail server, as well as the new virtualization tools.
The RHEL desktop isn't the place to look for the latest and greatest in GNOME developments. While GNOME 2.30 was released earlier this year, so far it's not part of the default RHEL 6 beta installation. At least for the beta GNOME remains at 2.28, Firefox is stuck at 3.5, and OpenOffice is at 3.1.
RHEL6 is what you want it to be, thanks to various install options
Red Hat has also gone the conservative route with a number of other GNOME packages. For example, it's opted for Pidgin over the less mature - but more feature-rich Empathy - that has largely replaced Pidgin in Fedora, Ubuntu and other desktop distros.
While many common software package haven't been updated to the latest releases that's to be expected from a conservative distro like RHEL, which has always erred on the side of stability rather than newest features.
RHEL 6 includes the same Nvidia hardware support found in recent Fedora releases and had no trouble automatically configuring out Nvidia graphics hardware.
Performance on the desktop matched what I've seen in recent releases of Fedora and Ubuntu - snappy even on somewhat dated hardware.
For casual desktop use, you're better off with one of the many free Linux distros available. As the name suggests, RHEL is aimed squarely at the enterprise market.
System Admins get some new tools in RHEL 6, most notably the new service System Security Services Daemon (SSSD), which provides central management of identities. SSSD also has the ability to cache credentials for offline use, handy if you're managing a large number of laptops that often leave the local network.
Of course, RHEL typically ends up on servers and there's good news to be found in the standard LAMP server stack. Just about everything is close to the latest stable version - Perl 5.10, PHP 5.3, Apache 2 and MySQL 5. Python remains at version 2.6 - it would be nice to have a parallel installable Python 3.x - and other software common on Cent or Debian servers (like Nginx and Memcached) remain absent from the basic RHEL server installation.
Red Hat hasn't yet set a final release date for RHEL 6, it is expected to arrive sometime before the end of 2010. In the mean time, you can grab the beta from Red Hat's website.
Is it worth the wait? For Red Hat's corporate and enterprise customers, the upgrade to 6.0 will be an important one - particularly those that need the virtualization and hardware support improvements. The only problem? That move from Xen to KVM, which may prove a stumbling block for many. ®