Upgrading from Linux to Solaris

Like many IT veterans, Sun Executive Vice President for Software Rich Green witnessed numerous enterprises adopting Linux in the 1990s to meet the demanding requirements of Web applications and services. Now Green is witnessing a new trend: Issues surrounding the long-term benefits and cost-effectiveness of Linux are causing IT managers to reassess the places where the operating system makes sense.

In this issue of Sun Inner Circle, Green explains why many enterprises today are opting to upgrade from Linux to the Solaris OS and how that's helping enterprises scale IT infrastructures to meet pressing business challenges.

Green is responsible for defining the vision and roadmap for Sun’s software strategy, including the Solaris OS, Java Enterprise System suites, N1 management software, and Sun Studio and Java Studio developer tools. Green’s perspective is based on more than 20 years of industry experience, 16 of which have been spent at Sun, and close involvement with industry-standards efforts and open source communities have contributed to his insights into the evolution of developer platforms and enterprise software.

INNER CIRCLE (IC): Let’s start out by asking a basic question: What was behind the initial appeal of Linux to support the Web tier of applications and services?

GREEN: People picked Linux in the past for a number of very good reasons. First, starting in the mid-'90s, the adoption of Linux was largely fueled by fast processors. Intel, for example, was producing processors for the desktop at a price-performance level so attractive that it made a lot of sense to start using commodity-based or volume-based application infrastructures. With the rapid growth of the Web tier, a free UNIX-like operating system coupled with inexpensive servers proved pretty attractive.

Second, the same period witnessed the increasing popularity of the open source development model. Having access to source code pushes innovation, and the kernel Linus Torvalds built became a nucleus for more people to add small innovations to Linux similar to the way that snowflakes form a snowball. Finally, after the dot-com bubble, economic realities made good enough technologies, rather than best-of-breed but expensive technologies, quite popular. So for some organizations, a low-cost operating system that performed adequately offered an attractive price-to-performance coefficient.

IC: Why did Linux become an attractive aspect of the scale-out mentality?

GREEN: The idea of pay as you go is always attractive. Starting small and adding more components as time goes by is typically one of the areas where IT and finance departments agree. So, using Linux on low-cost commodity systems helped architectures scale out in a way that seemed relatively painless. Also, Linux — regardless of the particular distribution — doesn't have a lot of complexity, which made setup and administration appear relatively straightforward.

Of course, the Linux operating system didn't have the robustness or scaling features found in large symmetric multiprocessing (SMP) systems. But the ease with which Linux can be hooked up to a lightweight database or file system gave a number of organizations the impression of limitless scaling.

IC: Have perceptions changed about using Linux in the enterprise?

GREEN: I hear a lot of talk emanating all the way from the datacenter floor to the executive boardroom concerning the unexpected challenges and hidden costs of using Linux. In the early days of corporate Linux adoption, many companies felt compelled to hire operating system teams to support Linux, and these groups would take something that was free, and spend substantial amounts of money and time modifying it to meet the specific requirements of the particular enterprise.

While the ability to modify is appealing to many developers — as well as one of the attractive aspects of open-source software — an operating system is an extraordinarily complex piece of technology. And the need to constantly tinker with the operating system necessarily drives up costs and negatively impacts overall productivity.

IC: But companies like Red Hat and Novell offer consulting services for optimizing Linux to mitigate some of that risk, don't they?

GREEN: They do, but they don’t provide those services for free. Of course, there's nothing wrong with charging a premium for a better product, but many companies have discovered that an OS that had first been presented as being “free” in cost actually incurs costs similar to or exceeding what, say, Microsoft charges for its operating system. Many companies are learning that while Linux is relatively inexpensive to acquire, it comes with high deployment and maintenance costs.

IC: Can you explain some of the risks associated with using commercial Linux distributions?

GREEN: If an enterprise is depending on an outside vendor and its particular Linux distribution to run enterprise systems, then support is probably a big issue. For example, Red Hat Enterprise Linux 3 is about to shift to a dramatically reduced level of support — and this is a matter of great concern to a number of companies that have come to depend on Red Hat’s services and support model. For its part, Red Hat needs to spend a substantial amount of time on engineering and quality assurance for new releases, and these costs — as with any other development cost — get passed to the users.

Unfortunately, these users now can’t be certain that the latest Linux distribution will be supported for very long — which is quite different than the Sun approach, which has always been about both support and development. Also, there is the potential problem of forked distributions. Recently, Oracle’s assault on Red Hat raises those issues. And Novell’s settlement with Microsoft also speaks to the churn around the concept of intellectual property in the Linux community.

IC: What about the long-term issues with Linux?

GREEN: The absence of upward binary compatibility in Linux development calls into question whether new distributions will have the ability to run current enterprise applications. In many cases, the absence of upward binary compatibility between versions of Linux requires significant engineering and quality assurance cycles in order to ensure that existing applications will continue to run well with new distributions of the OS.

IC: We’ve discussed some of the challenges with Linux, but what makes Solaris a compelling alternative?

GREEN: Solaris has always been superb on the back end. But to be honest with you, until a couple of years ago, the Solaris Operating System did not fulfill all the requirements of the edge and Web tiers. Today, however, Solaris has been optimized for the one-, two-, and four-way microprocessors used in AMD and Intel chipsets for many of the same servers that run Linux today. This means that the operating system provides an entire solution for both the database and presentation tiers.

Open-sourcing Solaris has also added to the long-term viability of the operating system because the speed of development has increased and interoperability with key open source technologies has improved. To date, there are over seven million commercial licenses out in the real world, and the businesses that rely on the Solaris OS are discovering that the operating system works hand in glove with popular Web infrastructure technologies like Apache, Tomcat, and MySQL.

IC: So how does Solaris now compare to Linux in terms of scaling out and scaling up?

GREEN: Both Solaris and Sun servers have been designed to support the needs of anything from modest initial deployments to full-blown datacenter installations. People often think of the Web tier as being these one- or two-way processors, but in high transactional environments — especially when things like SSL processing are required — Sun technologies like chip multithreading processor-based servers are compelling architectural choices in scaling up and scaling out consistently and reliably. This means that companies can now use an operating system that scales with growing demand, while having access to services and support simply not available in Linux distributions.

IC: From a feature-set perspective, does Solaris offer any advantages for the Web tier not found in commercial Linux distributions?

GREEN: Solaris contains a variety of alluring features, regardless of the scale or type of deployment — from database and application servers to presentation servers, and areas like high-performance computing and graphics processing. Part of this is due to the maturity of the OS. Solaris has enjoyed a series of refinements over the previous 15 years, which has resulted in a rich set of features that have been perfected over time.

For example, there’s the rock-solid reliability made possible by features like NFS for unlimited file serving capabilities, as well as DTrace for tuning and troubleshooting, as well as other capabilities like clustering, Predictive Self-Healing for availability, and even high-performance Web caching technology built into the kernel itself.

IC: Can you give examples of companies that have successfully taken advantage of Solaris features for the Web tier?

GREEN: A very large ISP in China called Sina comes to mind. This company replaced 30 Dell Xeon processor-based servers running Linux with 12 Sun Fire T1000 servers running Solaris 10 and the Sun Java System Directory Server. Another Sun customer, a European online gaming company called Mansion.com, replaced its x86 blade servers running Windows and Linux with Solaris 10 and Sun Fire servers. Both of these companies are seeing lower power and space-related costs, while increased reliability and availability gives their customers even better service.

IC: How about virtualization?

GREEN: Customers can use Solaris with VMware, of course, and even better, take advantage of built-in virtualization technologies like dynamic system domains and Solaris Containers. Containers provide a lightweight and low overhead form of virtualization that offers dramatic system resource utilization advantages over other virtualization software.

With Solaris Containers, Sun has made it possible to install just one instance of an operating system and deploy within it multiple, separately manageable, and optimized application environments. And, with the soon-to-be-released logical domains, Sun is bringing virtualization all the way down to the hardware level for even more flexibility on CoolThreads servers. The virtualization capabilities of Solaris lend scalability characteristics to systems in a way that Linux can't match.

IC: Plus, Sun has support for other virtualization technologies as well, right?

GREEN: Sun and the open source community continue to work on Xen-based virtualization technology that will convert Solaris or other operating systems into a Xen “domU” operating system that can be hosted in a virtual environment. But in the meantime, users who now upgrade from Linux to Solaris will discover how Solaris virtualization capabilities provide numerous advantages when it comes to virtualization, partitioning, and dynamic management.

On top of that, features like DTrace work in conjunction with virtualization technologies to provide unrivaled systems observability. One of the biggest challenges in making Web and edge deployments production quality is having the ability to observe, tune, and optimize incrementally over time. DTrace in particular is unique in the industry because of its abilities to safely perform these functions while the system is running in a production environment.

IC: From a business standpoint, what are the advantages in upgrading from Linux to Solaris?

GREEN: Three advantages come to mind: development time, cost, and reliability. Plus, Solaris brings these advantages without forcing enterprises to sacrifice one for the other. With Solaris, companies can start small with limited complexity, which helps them bring technologies to market quickly. These initial steps can be performed on low-cost hardware — which companies can upgrade over time. And, all of this can be achieved using the same application code base without hidden costs.

IC: So where does a company start in looking for resources to help investigate the benefits of upgrading from Linux to Solaris?

GREEN: Companies that use Linux for Web services and applications already have one of the best resources available for the upgrade — their Linux administrators. The Solaris and Linux operating systems have the same conceptual underpinnings. This means that an experienced Linux administrator can easily get up to speed to deploy and administer Solaris.

Sun also has a number of programs — from online guides to specific services — that help companies in upgrading from, say, Red Hat Linux or SUSE Linux to Solaris 10 — regardless of the kind of server that company may be using today. Sun services can help make the transition rapid in the short-term and viable for the long-term. This should give organizations comfort that the days of having to settle for a good enough operating system are now in the past.

About Rich Green
As EVP of Software, Rich Green is responsible for the overall operational leadership of Sun's software division, which has delivered some of the computer industry’s most innovative technologies and business models. Mr. Green oversees the Solaris Enterprise System, including the Solaris Operating System, the Java Enterprise System suites, N1 management software, Sun Studio and Java Studio developer tools. In addition, he leads a variety of industry-standards efforts and open source communities.