February 14, 2005

Red Hat Enterprise Linux 4: An overview

Author: Jem Matzan

Recently we had the chance to test out Red Hat's new version of its popular Enterprise Linux product, which Red Hat is officially unveiling today. The results were somewhat disappointing, as RHEL4 offers few compelling reasons for current RHEL3 customers to upgrade. For those considering new deployments, Red Hat Enterprise Linux 4 will be a more attractive option than its predecessor, but how will it fare against rival products from Novell, Sun Microsystems, and Mandrakesoft?

What's new in v4

Red Hat lists very few specific additions to Enterprise Linux 4:

  • The 2.6 Linux kernel has replaced the heavily patched and modified Red Hat 2.4 kernel, providing better scalability and expanded hardware support
  • SELinux security enhancements
  • Desktop software upgrades and additions: GNOME 2.8, OpenOffice.org, Novell Evolution, RealPlayer, Acrobat Reader
  • Integration with Active Directory authentication; also includes a Microsoft Exchange connector
  • EAL4+ certification pending

The list is a bit light. Considering Red Hat's zeal in backporting code from the 2.6 kernel to its own edition of 2.4, there is little left to be excited about in moving to 2.6 -- many of the features that made 2.6 a better choice have already been implemented in RHEL3.

Red Hat Enterprise Linux 4 includes the SELinux subsystem, which has been integrated with a dozen outward-facing services, including BIND, NTP, and Apache. This allows for policy-based mandatory access controls, which allows a finer control over user privileges.

The desktop software upgrades and additions are good for the Desktop and Workstation editions of RHEL4, but are utterly useless and somewhat of a liability on the AS and ES editions. Fortunately the software selection section of the Anaconda installer allows for fine-grained control over package installation. Cosmetically, the traditional BlueCurve theme for GNOME has been modified to match the one in Fedora Core 3; instead of the KDE-like menu interface, the standard GNOME top/bottom menu and taskbar split has been preserved. Some feel that this provides enhanced usability, but it may also provide an upgrade hassle for users accustomed to the old BlueCurve style.

RHEL4 is supposed to have better hardware support than previous editions, but it fared poorly with our standard test machines. While Red Hat Enterprise Linux was designed to work primarily with mass-market workstations and servers based on standard configurations, it should still work on custom computers like the ones we tested it with. The first system, based on an Intel D915GUX motherboard, refused to install properly on a serial ATA hard drive -- the ICH6R RAID controller was not properly supported. On our AMD64 test system based on an MSI K82 Neo2-FIR motherboard, we had some success with RAID arrays using both onboard controllers during installation. Despite being recognized by Anaconda, the boot loader hung when it came time for the first boot after installation. This is not the first time we've seen this SATA problem, but it's been around for so long that it seems ridiculous that Red Hat did not discover and address it during their testing process.

Outgunning the competition?

Red Hat's primary commercial competition in the corporate operating system market comes from Novell (a la SUSE Linux Enterprise Server and Novell Linux Desktop), Sun Microsystems (with Java Desktop System and Solaris 10), and Mandrakesoft (with its new Corporate Server and Desktop distributions). How do they compare?

Red Hat's main advantage over its competition is its diversity. Red Hat Enterprise Linux comes in four varieties: Advanced Server, Enterprise Server, Workstation, and Desktop. Each is customized for specialized purposes, but all are based on the same core. This ensures that customers have a variety of tools for a variety of tasks, rather than try to make one software solution fit all uses and machines.

Red Hat lacks integrated virtualization features like those found in SUSE Linux Enterprise Server 9 and Solaris 10, and it's more than three times the price of the comparably featured Mandrakelinux Corporate Server 3.0. But Red Hat's most dangerous competition may not be from outside companies, but from its own community distribution. We won't do an in-depth comparison with these distros, as their usefulness is dependent on your specific situation, preference, training, and infrastructure. Red Hat Enterprise Linux has been and continues to be a valid choice for pretty much any use you can throw at it. Whether it is the most cost-effective solution for your machines is a decision you'll have to make on your own.


In all, we found Red Hat Enterprise Linux 4 to be somewhat of a mediocre improvement to an already competent product line. It feels more like an update pack to RHEL3 than it does a full version upgrade.

RHEL4 will be free to Red Hat Network subscribers, but we don't think it's revolutionary enough to get people to switch from other operating systems -- at least, it's not any more revolutionary than it has ever been.

Purpose Operating system
Manufacturer Red Hat Inc.
Architectures i386, IA64, AMD64/EM64T, IBM zSeries, S/390 series, and POWER series
License GNU General Public License
Market Enterprise computing, from desktops up to high-end servers
Price (retail) Varies dependent on edition and subscription length
Previous version Red Hat Enterprise Linux 3
Product Web site Click here
Click Here!