IBM Guest Blog: Behind the Scenes of SUSE's 3.0 Kernel

Guest blog by Dan Frye, VP, Open Systems and Solutions Development at IBM

IBM has been a strong supporter of the Linux community and the open source development model for over 13 years and IBM is deeply involved in all phases of bringing Linux to market – from working upstream in the community to help make Linux better through working closely with our Linux Distribution Partners (LDPs) to ensure their offerings align with IBM’s hardware road maps and strategic software initiatives.  My role in IBM as responsible of all elements of Linux development has given me some insight over time into the software development processes of our partners.

The breadth of developer skills and the vast ecosystem contributing to Linux enables innovation and the delivery of technology by the community at an amazing rate.  Our Linux Distribution Partners have learned to harness and exploit this rate of change and deliver to the market at a similarly high rate.  A good example of this was SUSE’s plan, first expressed in the summer of 2011, to leap forward and incorporate the 3.x version of the Linux kernel in the middle of the SUSE Linux Enterprise (SLE) 11 product cycle on very short notice (deliver by 1Q 2012).

IBM Linux Distribution partners historically selected one kernel version to be the base of their product until the next major release. The LDP identified upstream kernel patches that align with customer feature requests, hardware enhancements, and improvements to include in the next version and begin to back-port those patches from newer versions of the Linux kernel into their designated kernel tree. The Linux Foundation says the typical kernel sees about 80 days of development^, yet most LDP kernels have a supported life of 10 years. While enterprises are running and supporting the 2.6 tree the community is turning out thousands of patches and advancing the kernel over many releases.

SUSE realized a kernel based on 2.6.32 would contain some 12,000 patches relative to the SLE 11 SP1 kernel. The SUSE engineering team decided on a more aggressive approach for their latest release,  looking to jump to the 3.x kernel to add available improvements and eliminate as much as 90 percent of the patches. This included back-ports of recent mainline functionality, bug fixes, and performance improvements made during the SP2 development phase.

As is normal, throughout SUSE’s development process IBM had access to betas and release candidates which were tested and certified by the IBM Linux Technology Center (LTC) and by our server test teams. Our joint test teams extensively, in partnership with SUSE engineering,  tested the entire operating environment (including the new 3.x kernel) and worked closely with SUSE to lock down and polish the eventual new SUSE Linux Enterprise 11 SP2 release.  It is a testament both to the upstream community for the quality of the base kernel and to the SUSE engineering team for their skill and experience in locking down new kernels in the SUSE Linux Enterprise environment that the entire process – from concept to market delivery – took only eight months and resulted in a now-typical high-quality release of SUSE Linux Enterprise.   Although it started as a very aggressive plan, the execution was smooth and it was good, clean fun to watch.