Red Hat Enterprise Linux 3.0

A multitude of enhancements make Red Hat Linux Enterprise 3.0 a natural for the data center, but licensing and support issues could hinder widespread adoption.

January 30, 2004

17 Min Read
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Thus the operating system had difficulty scaling to thousands of simultaneous threads, and Java-based applications requiring threading support were near impossible to deploy. NPTL was initially available in the 2.5 development seed of the Linux kernel, so distributions can incorporate back into the 2.4 source or use the 2.6 kernel.

Our tests revealed that RHEL 3.0 also delivers better storage management, including more robust drivers. We were happy to see support for SATA (Serial ATA)--we expect these faster disk drives to become more common as hardware vendors better integrate SATA devices. RHEL does not contain drivers for iSCSI disks because the driver does not meet the ratified specifications. Red Hat says it hopes to release an update to 3.0 that will contain this support.

REHL Support Options at a Glance

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We also were pleased to find that Logical Volume Management, authored by Sistina Software, has been incorporated into RHEL 3.0. This is a big plus for companies that require logical volumes. RHEL also supports software RAID for higher availability and reliability on hardware that does not natively support RAID configurations.

License and Registration, Please

But there is a catch (you knew there had to be one): Red Hat's purchase model--based on RHEL version, per server, per architecture, per support level per year--will be daunting to manage in large installations. Because customers are unlikely to install RHEL on all nodes all at once--instead accumulating an environment over many years to meet the demands of their businesses--purchasing agents could be renewing RHEL licenses and support every month.

Red Hat needs to ease this support burden by offering yearly support contracts that are renewable based on the server's classification and allow midyear purchases to co-terminate with a customer's existing support contract.

We installed all flavors of RHEL 3.0 from the same base media. Red Hat uses "Personality Technology" to customize the installation to WS, ES or AS--only the installation-boot CD differs. The company says this technology will let it create custom distributions of RHEL for large desktop rollouts or government organizations. All versions are supported by Red Hat technical support at various levels; the distribution also supports major independent software vendor applications, such as Oracle and IBM WebSphere, and includes desktop applications like Mozilla and OpenOffice, along with must-haves like Apache, Samba and NFS.

After installing all three versions, we examined the management functions of RHN (Red Hat Network) satellite and proxy servers. Installation was straightforward and easy to follow on the RHEL x86-supported hardware. All our test-bed devices, including network and sound cards, were installed and configured automatically. Previous users of Red Hat Linux or RHEL will feel right at home with the installer, which is based on Red Hat's venerable Anaconda installer interface.

The WS version is best-suited for desktop clients because it supports hardware with a maximum of two processors. However, the operating system will run on 32-bit architecture/x86 hardware, as well as 64-bit hardware, including Intel Itanium and AMD 64. WS is the least expensive variety, starting at $179 per copy without support, but it includes one year's worth of the RHN update module. Technical support, limited to 12/5, is available starting at $299 per workstation.

Unfortunately, Red Hat premium support, 24/7, is only available for the AS version. Although Red Hat aims this release at the desktop/client market or as part of a technical computing farm, the WS version could function as low-budget Web or file servers because it includes Apache and Samba and supports more than 8 GB of memory.

The ES version, targeted to edge network services like DNS, DHCP, Web, and file and print, runs only on x86 32-bit architectures with memory footprints smaller than 8 GB. Unlike WS, this version let us install Red Hat-supported packages, including DNS, DHCP, FTP and LDAP servers, and firewall services.

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Like WS, ES offers only standard support. Basic editions, those with only update support and no technical support, start at $349, and standard editions start at $799. If roughly $800 per copy sounds expensive, remember that it includes one year of unlimited technical support for Red Hat.

AS is Red Hat's premier edition of RHEL and boasts compatibility with a wide range of hardware architectures. This version of RHEL can run on typical Linux hardware, like x86, Intel Itanium and AMD 64, as well as atypical hardware, such as IBM pSeries, iSeries, zSeries and s/390 processor architectures. AS is supported on machines with very large processor and memory configurations--up to 16 processors and 64 GB of memory in x86 architectures (other architectures vary). RHEL AS is expensive compared with WS and ES, but it's the only version that offers 24/7, one-hour-response technical support--a must for mission-critical application servers.

Taking into account the less-expensive x86-based hardware and RHEL AS costs, AS is more affordable than Sun Microsystems Solaris or IBM AIX running on SPARC or pSeries servers. RHEL AS for x86 processors starts at $1,499 with standard support and increases to $2,499 for premier-level access. RHEL AS on zSeries and s/390 architectures starts at a hefty $15,000, which does not include premium support--tack on $3,000 for that!

We found the default package selection appropriate for each version, and the Red Hat installer let us customize the installation from the default selections. RHEL also lets administrators custom-compile applications on the operating system; this worked flawlessly on all three varieties when we compiled the latest version of the Apache Web server. Although custom applications are not supported by Red Hat per se, use of such applications does not invalidate the company's support offerings.

So you've decided to take the plunge and purchase a data center full of RHEL servers. But how do you manage them most efficiently? With the included RHN services, of course. RHN is a complete systems-management tool built on a simple Web-based interface and comes in three flavors: hosted, proxy server and satellite server. You can increase the functionality of the service by adding modules such as update, monitoring, management and, by the time you read this, provisioning.

The hosted RHN service module is the most common--and the one we've all grown to hate. For some time, Red Hat offered this module free for one system, albeit with limited availability due to its overwhelming popularity. Red Hat then discontinued this tack, turned the free service into demonstration mode and required demo users to complete surveys every 60 days to continue using the service. Of course, only those who were trying to use the service for free experienced these issues; paying customers enjoyed priority service and access to software updates. Ain't that always the way!

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If you were a victim of this situation, fear not: When purchasing and enabling a RHEL offering, this mode works great. After installing RHEL AS, we immediately connected to the RHN hosted server using the update module to grab the five or so software patches that were available at the time. The update module, called "up2date" on RHEL, is integrated into the desktop environment and checks in with the service regularly; it notified us when software updates or security patches were available.

For small installations of RHEL and those users who do not have bandwidth-restricted Internet connections, the hosted service will be sufficient. But because hosted mode requires that each computer make a direct connection to RHN over the Internet to check for and download updates, some sites will need an alternate plan.

Enter the proxy and satellite service offerings, which have many advantages for large RHEL customers. Both products bring the software inside the corporate firewall: One computer contacts Red Hat RHN servers, and your other servers contact that proxy or satellite server. The RHN database--and to a large extent the application server--still reside on the Red Hat RHN servers for the proxy offering, but the Web content and server are moved to the LAN. Updates can be pulled only with the proxy server from the client using the up2date software, though Red Hat says it is working on push capabilities.

Satellite mode provides the most flexibility by bringing the database, application and Web server to the LAN. Satellite can be run disconnected from the Internet, and you can load software updates via CD or DVD. The satellite service requires customers to have a separate license for Oracle, which RHN uses as its database back end; however, Red Hat says it is working to deliver an embedded version of the database in future releases.

After we picked the mode in which we wanted to run the RHN service, we selected the functionality we wanted included--for an additional cost, of course! The update module, which is included with every RHEL subscription, lets users update their installations on a yearly subscription model and provides priority errata notification via e-mail, an auto-updating ability and simple point-and-click installation with dependency checking. Most RHN users will be familiar with this mode.

The management module is an add-on to the update module, and its functionality differs depending on whether you're running hosted, proxy or satellite RHN service. In hosted mode, we found helpful system grouping, system permissions and scheduled actions capabilities. We were able to group systems into custom-created classes, and single systems could be members of many groups. This is especially useful if you want to group items by location but also need them grouped by application service. Once the management module was enabled in RHN, we could create users and give them specific permissions to groups or single systems. You also can perform scheduled tasks, like reboots, from the RHN service without having to connect to the machine.

This module also let us create custom channels and cache packages locally for delivery to managed hosts in proxy mode. With custom channels, administrators can distribute third-party RPM applications, for example, to hosts and system-management scripts. We created a custom channel, based on RHEL AS 3.0, then removed the ability to update and install office-productivity software, but your options are almost limitless. Feel the power.

In satellite mode, the management offering gave us even finer control. In addition to the hosted and proxy RHN offering, we could clone channels and create permissions based on channels instead of systems. This would be very useful in a staged environment, where you could create a channel for test machines. Once the software has been tested and validated, you could then clone it to your QA servers participating in the QA channel and eventually to the production machines.

We were given access to the management module and the proxy service offering, which was installed on top of RHEL 2.1 (currently, the proxy software is certified to run only on RHEL 2.1, which is included in the proxy option). Creating system groups and permissions for users was a snap. The software let us search the system database by item--installed software, installed hardware, IP address and location, for example. Creating custom channels was straightforward using a simple Web-based interface. The software is powerful, giving administrators an unlimited amount of customization.

The monitoring module is available only when using RHN in proxy mode and is a hardware-software product provided by Red Hat. The company is working to make this module available on the satellite server for customers that require disconnected RHN. We didn't test the monitoring module, but Red Hat says it provides autodiscovery; agentless monitoring of servers, including Unix and Windows servers; reporting; and notification. The monitoring software integrates into other monitoring packages, like Hewlett-Packard HP OpenView or BMC Software Patrol, using open APIs.

By the time you read this (or shortly thereafter), Red Hat will release an update to the RHN service that provides a provisioning module. This module was not part of our tests because Red Hat had not completed the documentation required for us to evaluate it, but the company says it will complement the management module and provide configuration management of RHEL machines, rollback capabilities and bare-metal recovery services.

The bare-metal recovery ability will use kick-start software through a GUI interface. The provisioning module will be able to track changes, based on delta actions, and roll back your server to a good known state. Using rollback and kick-start, it will be possible to clone a machine to another machine without much intervention, according to Red Hat. We can see where being able to easily transform unused development machines to production Web or mail servers when the load demands--among other uses that spring to mind--would be a strong selling point.

In our tests, RHEL worked flawlessly, and the addition of RHN should make it a good fit for most companies looking to go Linux. However, there's room for some improvements.

Atop our wish list: premium support for all releases, allowing ES to run on 64-bit platforms like Intel Itanium and AMD 64; larger memory footprints for ES; and changes in the licensing model.

Still, we're bullish: Given the ability to handle more threads via NPTL support in the kernel, Linux can now take on Unix. If you are considering a Unix-to-Linux migration, RHEL's features, management abilities using RHN, large installed base and support by the largest Linux vendor out there leaves others playing catch-up.

Red Hat Enterprise Linux 3.0, Red Hat, (888) 733-4281.

Christopher T. Beers is a Unix systems engineer at Syracuse University. His primary responsibilities include Solaris and Linux administration for machines used in academic computing, implementation of new services and support of existing services. Write to him at [email protected].

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Red Hat Enterprise Linux 3.0, the newest incarnation of RHEL, could be just what the doctor ordered to enable Unix-to-Linux migrations in large enterprises--thanks to its native support for POSIX-compliant threads in the Linux kernel, logical volume management, enterprise-class support options and full-featured Red Hat Network management platform. RHEL 3.0 comes in three versions to fit everyone's needs, pocketbooks and hardware architectures; and major software vendors like BEA Systems, Computer Associates International, IBM, Oracle and Sun Microsystems are certifying their software for use with the Red Hat release.

Still, though the product is ready for prime time, Red Hat needs to make some improvements if it wants to play in the same league as the big three Unix vendors. For example, its support model for renewing software is nowhere near as mature as the software and hardware contracts we're accustomed to seeing from HP, IBM and Sun. In fact, Red Hat's licensing will be well-nigh impossible for large data centers to manage. Furthermore, the introductory and midclass RHEL offerings, WS and ES, can't be upgraded to premium support, a pitfall for users who don't require the features of the top-end AS but consider their systems critical nonetheless.

Red Hat gave us authorization codes to download all three versions of Red Hat Enterprise Linux 3.0 for x86 architectures via the RHN (Red Hat Network)--a common distribution method used by Red Hat's customers. We downloaded the images, burned them to CDs and proceeded to install a network of RHEL servers and workstations in our Syracuse University Real-World Labs. This let us test various RHEL features and systems-management capabilities.

We installed RHEL AS (advanced server) on a multiprocessor server, ES (edge server) on a single-processor server and WS (workstation) on a desktop machine. AS was installed with logical volumes and software RAID configured, and with server-related software that would commonly be deployed on AS, including Apache and BIND.

ES was more basic, involving installing server processes, including Samba and NFS, on standard ext3 journaling file systems. Our workstation install was designed to mimic a Linux administrator's desktop and included software commonly used to build open-source software.

We tested all versions for interoperability among systems using the other versions. Examples of tests: We built open-source software on WS, used our AS box for DNS queries and delivered remote file services from our ES install.

Each install was connected to the RHN to grab all available updates at least once. Because the management module was enabled on our hosted RHN account, we populated and queried the database, verifying its functionality. We also searched the database by IP address and host name and looked for software installed on each via the Web tools provided with the hosted RHN management module.

Finally, we broke down the AS and installed RHEL 2.1 with Proxy RHN software. Once the AS was configured to act as our network's proxy server, we reinstalled the workstation and updated the software from the AS instead of contacting RHN directly.

Red Hat set up a demo satellite server so we could get the feel of how satellite mode performed. We used the Web tools to perform satellite-related tasks, including creating a custom channel based on RHEL 3.0 AS and then cloning that channel with ease.

Most of us have heard the buzz: Red Hat no longer creates a free open-source Linux distribution. As with most rumors, especially those that circulate throughout the Internet in a matter of hours, the reality has been twisted so severely that it contains only a tiny grain of fact.

Truth is, Red Hat has turned over development of its free Linux distro to the open-source community, discontinuing its Red Hat Linux Project internally and merging it with The Fedora Project (, an initiative the company sponsored. The two projects had very similar goals, and according to Red Hat, not having them work together was inefficient. Efforts are under way to combine infrastructures, documentation and Web sites to create a unified look, though the process will take months.

Boasting bleeding-edge technology, Fedora is the proving ground for improvements to Red Hat Enterprise Linux. Think of its role as developing enterprise Linux in the open-source realm. Whereas RHEL offers new releases every 12 to 18 months and supports those releases for five years, Fedora is much more aggressive. The project plans to deliver new versions, currently called Core releases, every six to eight months, and limit support to three months. So when Fedora Core 2 comes out, users will have only three months to update their hosts before security and bug fixes are no longer ported to Core 1.

The Red Hat engineering team that once worked on Red Hat Linux will be helping with the Fedora Core project, but will now encourage more outside participation. According to Red Hat, changing the name from Red Hat Linux to Fedora also resolves some troublesome trademark issues. By using this more open process, Red Hat hopes to provide an operating system that leverages free-software development practices and proves more appealing to the open-source community.

We installed the Fedora Core 1 release on a desktop-class machine in our Syracuse University Real-World Labs. Those accustomed to Red Hat Linux 9 installs will see little difference: The installer looks exactly like that of Red Hat Linux 9, only it's been rebranded to say Fedora Core 1. Certainly, there are more changes under the hood, but for the most part, Fedora Core 1 is Red Hat 9. In fact, remnants of Red Hat Linux are still there because the release information of Fedora Core 1 is still contained in the /etc/redhat-release file.

Although we were admittedly taken aback upon learning of the vendor's decision to discontinue Red Hat Linux, the company deserves a fair chance: It's still developing a free Linux, but now on a more aggressive schedule with a larger segment of the open-source community. The company's decision was a good choice all around.


Red Hat Enterprise Linux 3.0

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