Unbreakable Enterprise Kernel Release 2 has been released

We’re proud to announce the availability of a major enhancement to Oracle Linux: Unbreakable Enterprise Kernel Release 2 (2.6.39) has been released! The RPM packages are now available from the Unbreakable Linux Network and the public yum repositories. This kernel can be installed on both Oracle Linux 5.8 and newer as well as Oracle Linux 6.2 and newer. By simply updating the Unbreakable Enterprise Kernel, Oracle Linux customers can benefit from the latest improvements that have taken place in mainline Linux, without having to re-install their distribution or applications.

This release includes many new features as well as numerous performance and scalability improvements that were added to mainline Linux since the first Unbreakable Enterprise Kernel release (which is based on Linux 2.6.32). Despite the version number, the Unbreakable Enterprise Kernel Release 2 is based on mainline Linux 3.0.16 and includes a few selected patches from other mainline Linux versions. The source code is available from this public git source code repository.

Some key highlights in this release include:

  • Btrfs file system
  • Performance and scalability improvements
  • Virtualization improvements
  • Transparent Huge Pages and Memory compaction
  • Cgroups improvements
  • Linux Containers
  • OCFS2 improvements
  • Updated Device Drivers

For more information, please see the Unbreakable Enterprise Kernel Release 2 features and benefits document and consult the release notes for more For installation instructions, check out the Getting Started with the Unbreakable Enterprise Kernel installation guide on the Oracle Technology Network.

Now that the Unbreakable Enterprise Kernel Release 2 has been released, we will continue to provide support for Release 1 of the Unbreakable Enterprise Kernel (2.6.32) in the form of critical bug fixes and security errata for another 9 months. However, new hardware enablement (e.g. by providing device driver updates) will now only be made available through the quarterly updates of Unbreakable Enterprise Kernel Release 2 on the Unbreakable Linux Network. During this grace period, we encourage all customers to switch to Release 2.


Wonderful news, especially that it is for OL 5u8.

Will this impact the Oracle Server (Database) on OL6 certification? (I note that Certify still only lists OL4 & OL5.)

I admit surprise, however, that the Features document does not mention ASM.

Posted by Hans Forbrich on March 13, 2012 at 10:00 AM PDT #

does it have btrfsck?

Posted by guest on March 15, 2012 at 09:28 AM PDT #

Hans: this has no impact on DB certification on OL6. And the ASMlib kernel components are included in UEK2.

Guest: yes, it includes btrfsck that actually does repair btrfs filesystems.

Posted by Avi Miller on March 20, 2012 at 08:02 PM PDT #

Thanks. Thinking about the DB certification requirements a bit more, that makes sense.

Again, since ASMLib is part of UEK2, I am surprised that the Feature document for UEK2 linked above does not mention ASM support. Especially surprising considering how important Oracle has 'made' ASM to the Oracle DB Server, and how much we would like to see people default to UEK2 to support other Oracle product.

When I'm at a customer site and hand the feature doc to the customer's management, mention of ASM counts! Especially since KSplice on RH kernel that requires external ASMlib is potentially tricky, at least to explain.

Posted by Hans on March 21, 2012 at 07:27 AM PDT #

Hans, you raise a good point about ASM. I'll suggest that we look into updating the document accordingly.

Posted by Lenz Grimmer on March 21, 2012 at 07:36 AM PDT #

Will this impact the Oracle Server certification?

Posted by guest on March 30, 2012 at 06:09 PM PDT #

"Unbreakable Enterprise Kernel Release 2 (2.6.39) has been released!","the Unbreakable Enterprise Kernel Release 2 is based on mainline Linux 3.0.16". It is confusable that which version is UEK Release 2 really based on?

Posted by guest on October 11, 2013 at 05:26 AM PDT #

The UEK Release 2 is based on version 3.0.6 of the mainline kernel and we've made that quite clear. We retained the 2.6 version numbering because some userspace applications had an issue when the kernel version didn't start with "2.6"

For the UEK Release 3 (currently released as an RC), the version numbering is being changed to reflect the mainline kernel base, i.e. it will be versioned 3.8.18.

Posted by Avi Miller on October 11, 2013 at 02:34 PM PDT #

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