Oracle Unbreakable Enterprise Kernel Release 2 Release Notes (Quarterly Update 2)

Updated October 2012


  1. Introduction
  2. Notable Changes
  3. Driver Updates
    1. Storage drivers
    2. Network drivers
  4. Notable bug fixes
  5. Technology Preview
  6. Compatibility
  7. Known Issues
  8. Installation and Availability


The Unbreakable Enterprise Kernel Release 2 is Oracle's second major release of its heavily tested and optimized operating system kernel for Oracle Linux 5 and Oracle Linux 6. It is based on the mainline Linux 3.0 version 3.0.36. It contains a large number of improvements and new features that have been incorporated into mainline Linux since the first version of the Unbreakable Enterprise Kernel, which was based on Linux 2.6.32. Please see the initial Oracle Unbreakable Enterprise Kernel Release 2 Release Notes for a detailed description of these changes.

The 2.6.39-300 release is a quarterly driver update release which also includes bug and security fixes.

Note: the actual version number displayed by the kernel and on the RPM packages is 2.6.39. This was done to avoid potential breakage of certain low-level utilities of the Oracle Linux distribution (also known as the "plumbing") that potentially can't cope with the new 3.x version scheme. Regular Linux applications are usually not aware or affected by Linux kernel version numbers.

Notable changes

Driver Updates

The Unbreakable Enterprise Kernel supports a wide range of hardware and devices. In close cooperation with hardware and storage vendors, several device drivers have been updated by Oracle.

Storage drivers

Network drivers

Notable bug fixes

Technology Preview

Following features included in the Unbreakable Enterprise Kernel Release 2 are still under development, but are already made available for testing/evaluation purposes.


Oracle Linux maintains user-space compatibility with Red Hat Enterprise Linux, which is independent of the kernel version running underneath the operating system. Existing applications will continue to run unmodified on Unbreakable Enterprise Kernel Release 2 and no re-certifications are needed for RHEL certified applications.

The Oracle Linux team works closely with 3rd party hardware and software vendors to minimize impact on interoperability during releases but in order to introduce new drivers there are instances where changes must be made. In this release, there are changes to the kernel ABI which requires 3rd party kernel modules on the system be recompiled. Before installing this update, please verify the support status of this release with your application vendor(s).

Known issues

Installation and Availability

The Unbreakable Enterprise Kernel Release 2 can be installed on Oracle Linux 5 Update 8 or newer, as well as Oracle Linux 6 Update 2 or newer, both running either the Red Hat compatible kernel or a previous version of the Unbreakable Enterprise Kernel. If you're still running an older version of Oracle Linux, make sure to first update your system to the latest available update release.

The Kernel images are available as binary RPM packages from dedicated channels on Oracle's Unbreakable Linux Network as well as the public yum repository. There are four channels available:

Existing Oracle Linux 5 or Oracle Linux 6 installations can be upgraded to UEK2 by enabling the appropriate UEK_latest channel and running "yum update". The channel is automatically enabled for freshly installed Oracle Linux 6 Update 3 systems which shipped with UEK2-200.

For detailed instructions on how to download and install the Unbreakable Enterprise Kernel on Oracle Linux see the "Getting Started with the Unbreakable Enterprise Kernel for Oracle Linux" document on the Oracle Technology Network (OTN).

If you have questions regarding configuring or using Yum to install updates, please refer to the Oracle Linux Administrator's Solutions Guide

The kernel's source code is available via a public git source code repository from