Is Linux ready for the data centre?

With big-ticket vendors like Oracle and Dell now supporting Linux, the open source system has its sights firmly set on the data...

With big-ticket vendors like Oracle and Dell now supporting Linux, the open source system has its sights firmly set on the data centre. But does Linux offer a compelling high-end alternative to Windows and Unix?

UnitedLinux, the initiative launched on 30 May by Caldera, SuSe, Conectiva and TurboLinux, is as much an attempt to consolidate market share as it is to push Linux further into the enterprise.

The companies have clubbed together to create a standard Linux distribution that will reduce ISVs' investments in redeveloping their software for different Linux distributions. This promises to boost the availability of applications written for Linux.

The final UnitedLinux specification is due to ship in Q4, but its reception will be hindered by one notable absence; Red Hat, which has the lion's share of the Linux market, has no intention of joining.

Fiona Phelps, Red Hat's European marketing manager said the company was already conquering the enterprise space that the UnitedLinux team would like to be in. It signed deals with Oracle and Dell on 5 June, creating a holy trinity with which it will further attack the enterprise market.

Oracle 9i was ratified on Red Hat's Advanced Server, (joining 8i), and the Linux version of the product has been optimised for operation on the Red Hat system. Moreover, the database firm announced that it would offer technical support for Red Hat Advanced Server, and finally Dell announced Oracle 9i and Red Hat Advanced Server configurations on its hardware.

Whatever happens between the two rival camps, both UnitedLinux and Red Hat will be competing with Microsoft in the data centre market, where Windows 2000 is attempting to establish itself as a cheaper alternative to Unix. Microsoft will be making an even greater play for high-end corporate users later this year when the next release, ships.

Cash-strapped users, however, are facing an increasingly persuasive case for moving their corporate applications away from Windows to Linux. Microsoft's new licensing rules will do nothing to stop the rot - the firm's UK licensing manager Sue Page admits that companies preferring to upgrade infrequently could face higher licensing fees under the new regime.

Scaling the data centre
Cost is a prime factor in moving away from a Unix RISC box. For example, IBM's pSeries PowerPC boxes with eight-way capacity start at $61,000 (£39,000) for two processors, while its rack-mounted Intel Xeon-based xSeries 440 units with eight-CPU capacity and one processor installed is available at less than half that price.

The disadvantage is one of scalability between the Intel-based PC architectures and a Unix/RISC design. Users lose the ability to scale vertically when moving from RISC to Intel. In other words the number of processors that can be installed in an Intel-based server is limited.

"The prime motive for buying a Sparc box is scalability," says Gary Yeomans, technical consultant at Amdahl IT services. While Sun's 15000 boxes can scale to 106 processors, the Linux 2.4 kernel is far less scalable. Red Hat's Advanced Server only scales to eight Intel CPUs, for example.

This may not be a problem for the majority of users, who won't be running applications that need to scale vertically. Scaling horizontally by clustering servers will still enable you divide tasks among processors, as long as the tasks don't need a high level of intra-CPU communication, says Adam Jollans, Linux strategy manager at IBM. "At the entry level there are things that run on Intel that would have run on pSeries boxes in the past," he says.

Buying commodity Intel kit means that users can change their hardware configuration more easily than expensive RISC equipment as their requirements alter over time. On the other hand, users lose out on high-end advantages like IBM's copper processor technology, which improves the performance of its Power chips.

On the upside, IBM provides Linux from the workstation all the way up to its zSeries mainframes, and offers logical partitioning of Linux on the zSeries using Z/VM virtualisation technology and the iSeries (nee AS/400).

Managerial responsibilities
Management costs are also crucial to consider, but companies such as Red Hat are mirroring Microsoft's efforts here too. The company's Red Hat Network fulfils similar functions to Microsoft's Software Update Service, enabling administrators to update their servers with patches.
Jollans argues that because Linux comes from a command line user interface, it is more intuitive to manage than Windows 2000 systems where administrators are encouraged to use graphical management tools.

Along with the tools within the OS there are a number of commercial management tools available. For instance, Caldera sells the Volution Manager for managing Linux systems, for example. It provides a breakeven analysis for harried Linux administrators thinking of buying it. (see

Does integration stack up?
Managing the system well still leaves you with the challenge of integrating your Linux box with other systems, at various levels of the communications stack. Your clients will still probably be Windows-based, and secondly you will need to hook into applications on other back-end servers.

However, these challenges are becoming easier to solve thanks to the open source community. To hook your Windows clients into a Linux file and print server, use Samba. This is a freeware utility providing Server Message Block access to a Samba-enabled server. SMB is the protocol that Windows clients use for file and print access to Windows servers.

As more products become Linux-enabled, application-level integration with other back-end systems will be less of a problem. IBM's WebSphere application server, which runs on Red Hat Linux, handles integration with systems including legacy applications, and with software like Oracle 9i, DB2, JD Edwards and SAP either ratified or in the process of ratification on Linux distributions, hooking Linux applications to the rest of the software infrastructure will be as easy as integrating any other system.

Care in the community
When a user is facing a challenging integration issue, Yeomans argues that the benefit of Linux over Windows and Unix is its support network. "You have to be a fairly large organisation before the likes of Sun and Microsoft will listen to what you're saying [when something is wrong with the operating system]," he warns.

With Linux there is a support network of genuinely interested developers that make up the Linux community. This should make it easier for smaller businesses to influence how the OS is evolved.

Clearly, Linux is thwarting many people's predictions by slowly clawing its way into the data centre. The key challenge for Linux vendors is still to convince users that they can trust it. The good news is that suppliers such as IBM, Dell and Sun are helping by releasing their own Linux-based products and making the operating system compatible with their own brands of Unix.

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