ServersRed Hat Linux: A popular Linux distribution that bridges the world of...

Red Hat Linux: A popular Linux distribution that bridges the world of UNIX and Windows




Linux is Linux is Linux. Or is it?

Not really. Despite the fact that at the core — the kernel — every Linux distribution is based on the Linux kernel released by Linus Torvalds and his posse of volunteers, there are some major differences between Linux distributions, as vendors seek to assert their individuality in the marketplace.
Linux is Linux is Linux. Or is it?

Red Hat Linux is one of the most popular Linux distributions, and Red Hat has distinguished itself in the marketplace by positioning Red Hat Linux as an easy-to-use, easy-to-install Linux distribution backed with a support staff. That the support is somewhat limited — if you purchase a higher-end Red Hat Linux bundle, you’re entitled to 30 days of free telephone support to tackle installation and configuration issues — doesn’t detract from the fact that Red Hat is aggressively pursuing Windows users who are seeking an alternative. As a result, Red Hat Linux is the most “Windows-like” of the Linux distributions. It also means that Red Hat Linux is in many ways the quirkiest of the Linux distributions.

Quirky? Yes. While most Linux distributions offer basically the same tools (mostly open-source software from the Free Software Foundation, the Apache Group and the XFree86 group), Red Hat has aggressively developed its own tools for installation and configuration. While these tools have been released as open-source software, they haven’t yet caught on in the rest of the Linux community. The Red Hat Package Manager (RPM) software-bundling format is used almost exclusively by Red Hat users, even though it’s available for any Linux distribution. Similarly, Red Hat has been pushing the GNOME interface — which at best is immature and barely stable — while de-emphasizing the KDE desktop, a much more mature technology that’s found a wider acceptance among the greater Linux community.

A Great OS for Internet Use

However, the core of what makes Linux a great operating system for Internet/intranet usage is present in Red Hat Linux 6.0. And still, Linux politics shouldn’t deter you from looking at Red Hat Linux as an Internet server platform. With version 6.0 — which incorporates the new and improved Linux kernel 2.2 — Red Hat Linux can be taken seriously as a workhorse for Internet server usage, adding symmetrical multiprocessor (SMP) support, improved NFS performance, and enhanced RAID support.

With SMP, Red Hat Linux scales better on machines with multiple processors. Though SMP support is not new in Linux — version 2.0 of the kernel incorporated some rudimentary SMP support — the SMP overhaul in 2.2 features an overhauling of the interrupt handling and how the corresponding locks are called and executed. As a result, Red Hat Linux on an Intel platform scales well to four CPUs and works on up to 16 CPUs. That same level of performance extends to the SPARC platform (where the SPARC32 version scales well to 4 CPUs, and the SPARC64 version scales well to 12 CPUs while working on up to 64 CPUs) and the Alpha platform (where Red Hat Linux works on dual 21264-based machines). Additionally, interrupts are dynamically routed to all CPUs, and interrupt handlers are fully threaded.

Another enhancement in the Linux kernel 2.2 is in RAID, which offers system redundancy via multiple disk drives and the creation of larger virtual volumes. Red Hat Linux 6.0 offers both hardware support (including direct support for AMI MegaRaid, DAC 960, and Compaq SmartArray controllers) and software RAID support, with software support managed directly by the kernel. There’s support for full RAID levels 0, 1, 4, 5, and linear support, as well as a threaded rebuild process and kernel-based configuration. In addition, there’s the ability to hot swap storage devices managed by the operating system.

Finally, those overseeing Internet installations will appreciate the new support for larger memory spaces. On an Intel or Alpha platform, the memory system will autodetect up to 1 gigabyte of RAM and can support up to 2GB with a kernel reconfiguration. On the SPARC32 platform, up to 3.5GB is supported, while the SPARC64 platform supports up to 64GB of RAM. In addition, there’s support for a single swap partition up to 2 gigabytes in size.

Internet Tools in Red Hat

As far as specific Internet tools are concerned, Red Hat Linux 6.0 includes the Apache HTTP Server, sendmail, the WU-FTP server, a DNS server, several Usenet servers and a print server. At this point Red Hat is not offering a secure-server bundle based on Red Hat Linux 6.0, although an older version of Red Hat Linux does include a secure Web server for Internet commerce. Still, none of these applications — including the secure Web server — is unique to Red Hat Linux; they all can be found as part of other Linux distributions. A variety of secure Web servers will run on Red Hat Linux, including Stronghold. However, Netscape is not yet supporting a version of Netscape Enterprise Server for Linux, a curious omission considering the overall corporate commitment to Linux.

Even though Red Hat is pushing GNOME, Red Hat Linux 6.0 does include the KDE interface. In a way this political battle is rather irrelevant when considered in a server context, because most system administrators (especially experienced UNIX system administrators) will be more comfortable administering Linux from a command-line interface.

RPM, while not widely adopted in the Linux community, is still a useful piece of software, and as Linux matures it will need to adopt RPM or something like it to gain acceptance in the corporate community. RPM automatically installs and updates the operating system and applications, letting system administrators more easily distribute Linux across an enterprise. Still, there’s not the high level of system-administration tools in Linux that you’ll find in a more mature UNIX implementation, such as Solaris.

Other Linux distributions have included support for the egcs (Experimental GNU Compiler System; pronounced eggs) compiler, and Red Hat Linux adds support for version 1.1.2. While the traditional GNU gcc compiler is still included with Red Hat Linux, egcs is catching on a more efficient and feature-rich C/C++ compiler. With egcs, name spaces are now fully supported, exception handling is now thread-safe and protected virtual inheritance is supported. In addition, there’s enhanced performance on Pentium-based systems, while the SPARC port includes V8 plus and V9 support as well as performance tuning for Ultra class machines.

For an Internet installation, Red Hat Linux 6.0 now includes traffic shaping, where a Linux router controls the amount of bandwidth that is used by various network devices and ports, and support for both GigEthernet and IPv6. In addition, there’s kernel-level support for NFS, which improves performance and makes the NFS support more scaleable. Red Hat Linux officials claim that the move to the kernel –as well as some other enhancements and support for NFS v3 — increases NFS performance by up to 40 percent.

Linux is proving to be one of the most popular — if not the most popular — operating systems for Internet/intranet serving purposes. With a host of performance enhancements that will benefit Web sites and Internet sites of all sizes, Red Hat Linux (and, more importantly, Linux kernel 2.2) is a stable and high-performance operating system for Internet usage.

Pros: New support for SMP and RAID arrays; Improved compiler performance; Better network-management tools

Cons: Reliance on Red Hat tools to the detriment of system administrators; Administration tools are less sophisticated than those found in more mature UNIX versions; Much-touted support is limited to 30 days

Version Reviewed: 6.0

Reviewed by: Kevin Reichard
Last Updated: 5/6/02

Date of Original Review: 5/5/99

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