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When to use Unix or Linux, part 2: Applications and support

Compare Unix and Linux in terms of their availability, virtualization, scalability and server consolidation options and support.

In Part I of our report on choosing Unix or Linux, we discussed the questions you might ask when considering either Unix or Linux. They involved issues such as SLAs and current knowledge of existing support teams. We also discussed architectures outside of x86 environments such as IBM's System p - which allows one to run Unix and Linux concurrently on one physical server. Finally, we also touched on some technical topics such as endianness.

In this tip, we'll delve more into application-related issues and look more deeply into support, while also discussing relevant topics such as virtualization and how issues such as server consolidation fit into the mix.

Unix or Linux application choices
In recent years, most of the larger enterprise applications vendors have ported their applications to Linux. Several years ago – when considering whether or not to implement an Enterprise Resource Planning (ERP) application, your OS options were either Unix (AIX, Solaris or HP-UX) or Windows. In most cases, you will find that today all the larger vendors have ported their applications to Linux. This includes the big-boys such as PeopleSoft, SAP, and Oracle eBusiness Suite.

This is really exciting and bodes well for Linux moving forward. Naturally, besides the actual port, other issues that need to be considered include availability and support. In most cases, vendors have more experience deploying and supporting application's on Unix environments than Linux. Why is this important? If you are already supporting an enterprise ERP application supporting thousands of users, you'll already know the answer to that question. In today's world, IT organizations are usually required to keep applications up and running around the clock - 24x7.

Because the maturity of Linux vendor support (we're not talking Linux as an O/S) is not as established as Unix vendor support, this is certainly an issue that needs to be considered. On the other hand, many large vendors have thrown themselves behind Linux in a big way.

Case in point - Oracle and their Unbreakable Linux program. This is Oracle's Linux support -based program which competes directly with Red Hat for support of the Linux operating system. Oracle has four tiers of support, including free installation of binaries, Enterprise Linux Support, Basis support and Premier Support. Oracle even has its own Linux distribution – Oracle Enterprise Linux, which further illustrates the way in which Oracle views Linux.

IBM is another example of a vendor which has really supported Linux through the years. Their commitment started in 2001 – with a 1 billion dollar support commitment. Today, they fully support Linux partitions on their midrange System p platform, as well as their mainframe System z architecture. They actually have over 600 developers working in their own Linux technology center – supporting over 100 open source community projects. IBM has also facilitated more than 3000 migrations to Linux, many from Solaris and has over fifteen thousand Linux customer engagements.

OS and server consolidation
Without a doubt, server consolidation is one of the most important projects most companies get involved in today. Companies consolidate their server farms to increase efficiencies and to save money on hardware and support costs. Because Linux can run on so many different types of hardware, generally speaking it makes more sense to consolidate to Linux rather than Unix.

Linux runs on x86 machines, Unix hardware vendors' machines from Sun, HP and IBM, and it can even run on IBM mainframes. Simply put, there is no single other operating system that can run on so many different types of architectures.

Why is this important? Consider your in-house support costs. If you're a Fortune 500 company, chances are you're paying a huge price by supporting several different versions of Unix and Windows. Standardizing on one operating system such as Linux allows you to reduce the amount of technical talent supporting your infrastructure. This includes IT support in the form of engineers, administrators, architects and operators.

Vendor support costs are reduced as well. For example, if you've standardized on Linux, you won't need to also have contracts supporting your Unix and Windows operating systems. At the same time, your overall hardware costs should decrease.

Most organizations which perform some kind of OS consolidation will also go through a hardware server consolidation program. At the end of the day, this allows them to support fewer servers and also to maintain fewer support contracts with vendors. Oftentimes, software licensing costs also decrease. This is because IT can be in a position to further consolidate application and database environments.

Throw in the complexity of virtualization and OS consolidation becomes that much more important. Let's look at Unix. On the virtualization front, consider that IBM's AIX has PowerVM, Sun's Solaris has xVM, containers and LDOMs, and HP's HP-UX has vPARs and Integrity Virtual Machines.

It is true that Linux distributions themselves often have their own forms of virtualization. Yet if you go further and consolidate on one Linux distribution, you can have one strategic corporate strategy. For example – if you stay with RHEL5, you can use their XEN based implementation.

The only caveat I will toss in is that if you are planning to run Linux outside of the standard x86 architecture, you may have to use your vendor's proprietary solution for virtualization. An example of this is IBM's System p. While you can run either SLES or RHEL on this platform, you will need to use IBM's PowerVM solution on their architecture.

The case for Unix
As a Unix administrator from the 1980s, I will say that Unix is unquestionably still the more mature product. Linux has made substantial strides in recent years – particularly since the advent of the Linux 2.6 kernel – for environments that require the maximum amount of availability, scalability and performance. Unix is still king of the hill.

This is particularly relevant when it comes to Relational Database Management Systems (RDMS). Linux still comes in third in overall market share to Unix on RDMS. Why is this so? The folks who spend the money are usually the most conservative ones. Chief Information Officers (CIOs) are very comfortable with Unix and - right or wrong – there is still a perception among some that Linux is an operating system meant for hackers, or only for running corporate email systems.

Linux has definitely come of age and is a viable option for the most critical of applications. In many cases, it has the same world-class vendor support that Unix has enjoyed for years. Furthermore, organizations have recognized that they can save a tremendous amount of money by consolidating their OS support around Linux. The bottom line is – Unix or Linux?

You can't go wrong with either choice. If nothing else, this answer is a huge win for Linux!

About the author: Ken Milberg is a systems consultant with two decades of experience working with Unix and Linux systems. He is a Ask the Experts advisor and columnist.

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