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Introducing the Linux 2.6 Kernel

Introducing the Linux 2.6 Kernel

Already the subject of intense scrutiny, this new kernel will be the first major revamp of the Linux kernel in two years. We at Open Source Development Labs (OSDL) have worked with Linux developers and together completed more than 4,000 tests on publicly available development versions of this kernel.

In recent months, we have run the development kernel, known as 2.5, in our production environment with servers, achieving more than 30 days of continuous uptime. The 2.5 kernel will transition into 2.6, and OSDL is committed to its rapid adoption in the market. (OSDL is a global consortium backed by Computer Associates, Fujitsu, Hitachi, HP, IBM, Intel, NEC, and other major vendors.)

A fast and deep entry into the market would be a distinct change from what happened with Linux 2.4, when adoption took longer than the industry anticipated. This time around, however, the development community, including OSDL, has tested the kernel so extensively that we believe adoption will come much, much faster.

There are eight reasons why CIOs will decide to upgrade to a Linux distribution based on 2.6: seven related to performance and the eighth, and critical, factor being cost. At OSDL, we divided the key 2.6 kernel feature improvements into seven categories: performance, scalability, availability, clustering, I/O, management, and serviceability. We found that Linux systems based on the 2.6 kernel will scale better on bigger machines. This provides the opportunity to replace more proprietary Unix servers and to consolidate workloads on bigger Linux systems. But it's not just the technical features; the clincher is the cost savings that these features will make possible for large organizations.

Businesses can save big money by implementing the new Linux kernel on Intel architecture-based servers. Amazon's move from Solaris to Linux on HP NetServer systems helped Amazon slash its technology capital budget more than 25% in the first year alone. There's more: businesses can achieve lower training costs, and additional savings can be found as Unix technical staff can easily port their skills, procedures, and even many applications to Linux.

To borrow an insight from Clayton Christensen's book, The Innovator's Dilemma (HarperBusiness, 2000), Linux is a disruptive technology. The new kernel is going to allow Linux to pass Christensen's "good enough" test. This means that many organizations are going to begin moving their core data center operations over to Linux. It gets the job done for a lot less money. As proprietary architectures yield their performance advantage to Linux, Linux becomes "good enough" for most workloads.

Scalability
"Does Linux scale?" is often the first question an IT manager will ask when evaluating whether Linux can replace an enterprise Unix server. Our tests indicate that the Linux 2.6 kernel will scale much better than the 2.4 kernel. Most of the development of the 2.4 kernel was done on single-processor systems with some testing on dual-processor and larger systems. The larger 8- and 16-way machines are supported, but the 2.4 kernel isn't really aimed at those system sizes. With the 2.6 kernel, performance is dramatically improved on large machines.

As part of OSDL's charter we provide outside developers access to enterprise-class machines. Testing on multiprocessor machines is a vital part of the Linux development process and has resulted in an improved scheduler, kernel native threading, and overall refinement of the locking granularity.

We also did a lot of testing of these larger machines with databases, which are a classic resource-intensive, business-critical workload. OSDL provided the Database Test Suite, a fair-use implementation of Transaction Processing Performance Council (TPC) benchmarks. These database performance test results comparing the Linux 2.4 kernel to the Linux 2.5 kernel are freely available from OSDL at www.osdl.org/projects/performance. The source code for the tests is also available for developers.

Stability
"Is Linux stable on larger systems?" is probably the second most frequently asked question. OSDL put a lot of time and resources into testing the Linux 2.5 kernel through the Linux Stabilization Project. A description of the tests and results is available at www.osdl.org/projects/26lnxstblztn/results. Based on these tests and our experience with the 2.5 kernel, we expect that the Linux 2.6 kernel will be more stable than the Linux 2.4 kernel was when it was released.

There is a companion project to test scalability in a repeatable scientific environment. OSDL's Scalable Test Platform (STP) and Patch Lifecycle Manager (PLM) provide the Linux development community with an open, easy-to-use resource for testing custom kernels. STP works as the testing engine. PLM makes it easy to manage developers' patches against stock kernels. With a consistent set of hardware and test suites, developers can test new features in a controlled environment.

Planning for the Future
Because of the improvements in scalability, stability, performance, and availability in the kernel, Linux has reached the level where it can replace more expensive Unix servers. IT managers need to evaluate Linux suitability for their data centers based on the features it will have at the time of deployment. The rapid development of Linux adds some challenges to plans to adopt it. IT managers need to become familiar with the improvements to the 2.6 kernel, determine suitability for their enterprise, and insist on these features when preparing Request for Proposals (RFPs) or making a purchase.

The Linux 2.6 kernel will support more hardware platforms, bringing businesses savings in reduced management costs through a reduction in the number of operating systems under management. Instead of a variety of Unix versions, businesses can standardize on Linux on a range of hardware architectures. Most of Linux runs on industry-standard Intel architecture servers, available from almost every vendor, including Dell, HP, IBM, and NEC. Linux also runs on mainframes from IBM and Fujitsu, PowerPC-based servers from IBM, and Itanium-based servers from HP.

When IT managers plan for the future, they should keep in mind that Linux server use is growing and Unix server use is shrinking. According to industry research firm Gartner, hardware vendors shipped over 425,000 servers with Linux last year, up from 286,823 in 2001. During the same time period, shipments of Unix machines fell 9%. Due to technical improvements in the 2.6 kernel, we anticipate that this trend will accelerate. Many more companies will follow Amazon's early lead and realize significant cost savings by migrating from Unix to Intel architecture hardware.

With the release of the new kernel, OSDL is refocusing much of its work on end-user Global 2000 corporations. We're interested in learning more about your plans to use Linux. What challenges remain before you are prepared for production deployment? With classic disruptive technologies, much like the original personal computer, we know that adoption of "good enough" technology accelerates in new and surprising ways. Tell us what your plans are for Linux. We invite your organization to participate with OSDL in making Linux ready for your enterprise.

For More Information
Learn more by visiting www.osdl.org, the OSDL site. Here you'll find information on Carrier Grade Linux, Data Center Linux, OSDL Database Test Suite, Linux Stabilization Project, Scalability Test Platform, Patch Lifecycle Manager, and much more.

What Is the Kernel?
The Linux kernel is the core of a Linux system. It is only a small part of the large number of files that are installed on a server's hardware. Programs like Web servers, databases, application servers, mail servers, compilers, text editors, image editors, and word processors are not part of the Linux kernel. The kernel controls access to system resources such as

  • CPU
  • RAM
  • Monitor, keyboard, mouse
  • Disk drives, CD-ROM drives
  • Tape drives, printers, and other peripherals and ports
  • Network access

There are two types of Linux kernels, development and production (or stable). Development kernels end in an odd number (e.g., 2.3 or 2.5). Production kernels end in even numbers (e.g., 2.4 or 2.6).

This numbering scheme divides Linux users into two categories. The first category consists of developers and testers, who use the odd-numbered kernels, which are changing and may be unstable. The second category consists of production users, who use even-numbered kernels, which change as little as possible.

Although there will be some settling of the fine points of kernel feature implementation and a deferral of features that aren't ready for production, a look at the 2.5 kernel will give a fairly good view of what the 2.6 kernel will become.

More Stories By Dave Fuller

Dave Fuller brings more than 25 years of data center technical and marketing experience to his current position leading the technical marketing group at OSDL, where he participates in both the Linux kernel stabilization project and the Data Center Linux working group. Prior to OSDL, Dave led IT activities at a start-up focused on Web commerce. At Sequent Computer Systems, he played key roles in technical services and oversaw technical sales support for the company's Asia-Pacific and Latin American operations.

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Marky Goldstein 10/01/03 04:51:14 AM EDT

The Linux kernel should be improved for realtime audio- & video processing and clustering... ! That's home entertainment in the future...