Open Source

Red Hat Enterprise Linux 3: An overview

Take a calm look at the most important features of this impressive product.


It seems like everywhere you look, there's an article about Linux and its place in the enterprise. Does it really have a lower TCO than Windows? Does SCO really own Linux IP? Is Linux going to take over the desktop through an all-out assault on Windows XP?

It’s going to be an interesting couple of years to watch all of this play out!

In the meantime, there continue to be interesting technical and business developments in Linux-land. One of the newest enterprise versions of Linux on the scene is Red Hat’s Enterprise Linux 3—the latest version of Red Hat’s industrial strength open source server. After reading about the controversies regarding Linux, how about a refreshingly calm look at a most impressive product? Read on.

Red Hat’s history
Until recently, Red Hat maintained two distinctly separate product lines. The most well known product line—now discontinued, at least in its old form—was called Red Hat Linux and was the consumer and home user oriented product. The second product line that continues to be maintained is its high end server line: Red Hat Enterprise Linux (RHEL).

The old Red Hat Linux product has been incorporated into a new service called the Fedora project and is now a more community-influenced effort, although Red Hat continues to contribute significant resources to the project and has control over the product.

How does this fit in with RHEL? The Fedora project will become the testing ground for new technologies that might eventually make their way into RHEL. The goal of RHEL is to provide a stable, consistent, and robust platform upon which enterprise-class applications can be deployed. The Fedora project, in contrast, will focus more on the “latest and greatest” technologies and will likely not be as consistent as RHEL.

About Red Hat Enterprise Linux
Red Hat’s Enterprise Linux product line is comprised of three separate editions: The WS, ES, and AS editions (see Table A). The WS edition is aimed primarily at the high end technical desktop; the ES edition is targeted for small office or departmental servers, while the big-iron AS edition is intended for large, mission-critical database servers.
Table A

AS

ES

WS

Kernel

2.4.21 enhanced

2.4.21 enhanced

2.4.21 enhanced

X86 (except AMD K6)

Intel Itanium2

AMD64

IBM z, i, p, S/390

Maximum CPUs

16

2

2

Maximum RAM (x86)

64GB

8 GB

64GB

Maximum RAM (Itanium2)

32GB

N/A

32GB

Maximum RAM (AMD64)

16GB

N/A

16GB

Table A - Red Hat Enterprise Linux editions comparison

All editions include packages you would expect including Apache, Samba 3, NFS, and other server applications. All editions also include desktop applications such as OpenOffice, which is very appropriate for the WS edition and might be useful in the AS and ES versions.

What’s so good about it?
A very common question about Red Hat Enterprise Linux is “Why should I buy and pay for RHEL when I can just download Red Hat Linux 9 or Fedora Core and use it for free?” It’s an excellent question. There are certainly many instances in which the “free” product is more than sufficient. For example, for a small Web server, a DHCP/DNS, or other infrastructure server for testing, Red Hat Linux or Fedora Core will do. There are two primary benefits in RHEL, however: stability and support. RHEL features a 12-18 month cycle between major releases while RHL and Fedora Core have 4-8 months between releases. For a company that operates dozens or hundreds of servers, the longer release cycle allows ample time for testing and implementation on a reasonable schedule before the next major release hits. A 4-8 month release cycle is simply too fast for many organizations.

Furthermore, except in the event that a security problem warrants a change, the ABIs and APIs in each RHEL major release will not change, meaning that you won’t need to make modifications because of a change to these components. An ABI is a binary interface while an API is a programming interface.

Support differences
The argument could be made that these organizations don’t necessarily have to upgrade to the current release as soon as it comes out. However, for companies that depend on Linux to run their operations, operating system support is a critical component in their infrastructure. Red Hat Network (RHN) errata support for Red Hat Linux 9—the last of the non-Fedora Core based distributions—will be ending April 30, 2004. Red Hat provides maintenance for non-enterprise platforms for only 12 months. The RHEL platforms, on the other hand, come standard with one year of support, and customers can continue to obtain support for five years. Product updates are provided a few times a year for the RHEL series.

Sure, if a company decided to standardize on Red Hat Linux 9, support could be obtained from other sources, but the cost to maintain the servers would jump accordingly. In the long run, TCO costs can be stabilized through the use of a platform that can be reasonably supported for a longer period of time.

Enterprise support options
RHEL products can be supported through one of three support programs which Red Hat names Basic, Standard, and Premium. Basic support is the lowest level of support, and while it doesn’t actually provide actual support for problems, it does provide access to the Red Hat Network. Standard support offers live supports from 9AM to 9PM Monday through Friday with four hours response, while Premium support extends these hours to 24 x 7 with a guaranteed one-hour response. See Table B.
Table B

Basic

Standard

Premium

Technical support hours (phone)

N/A

US:
9AM to 9PM ET, Mon -Fri

Global:
9-5 GMT/CET Mon - Fri

24 x 7

Technical support hours (web)

24 x 7
(30 days)

24 x 7

24 x 7

Response time

N/A

4 hours

1 hour

RHN included

Available for AS

Available for ES

Available for WS

Table B - RHEL support options

Improvements
RHEL 3 sports a number of improvements over older versions. First, RHEL is available immediately on seven architectures (AS) meaning it will work on just about anything you want to throw it on. Second, while RHEL 2.1 could handle up to 8 processors and 24 GB of RAM, RHEL supports up to 32 processors and a dizzying 64 GB of memory, meaning it is suitable for even the most intensive purposes. Furthermore, RHEL 3 supports serial ATA devices (SATA), which were not supported in RHEL 2.1.

RHEL 3 also boasts other enhancements which bestow better scalability, performance, and manageability upon the product line. For example, native POSIX threading provides improved performance for multithreaded applications such as Oracle and Java. RHEL 3 also sports a new storage manager which precludes the need to purchase an expensive LVM product.

The RHEL 3 product line provides a company with the ability to deploy a desktop-to-data center solution based on a common platform.

Pricing
If you’re a hobbyist or Slackware veteran, it might appall you that Red Hat is charging for Linux, especially when the latest Debian distribution can be downloaded for free and easily installed. However, consider the enterprise environment where consistency and supportability are key factors in a software solution. A few years ago, some companies wouldn’t consider Linux because there was no one to which a finger could be pointed if there was a problem. Red Hat has handily erased this mantra with the release of RHEL.

Pricing depends upon the support option you select and the platform you desire. See Table C. Of course, contact Red Hat for more accurate pricing information. Bear in mind that these prices are an annual subscription fee.
Table C

Basic

Standard

Premium

WS

$179

$299 (x86)

$792 (Itanium2, AMD64)

N/A

ES

$349

$799

N/A

AS

N/A

$1,499 (x86)

$1,992 (Itanium2, AMD64, IBM i, p)

$15,000 (IBM z, s390)

$2,499 (x86)

$2,998 (Itanium2, AMD64, IBM i, p)

$18,000 (IBM z, s390)

Table C - RHEL pricing

Summary
As I indicated earlier, RHEL 3 is not for everyone. If you’re a hobbyist or a very small company that doesn’t want to have to pay an annual software subscription fee, RHEL isn’t for you. Take a look at Fedora instead. If, however, you want to deploy Linux applications on a robust, stable, well-supported platform at a reasonable price, RHEL 3 just might fit the bill.

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