The software described in this documentation is either in Extended Support or Sustaining Support. See https://www.oracle.com/us/support/library/enterprise-linux-support-policies-069172.pdf for more information.
Oracle recommends that you upgrade the software described by this documentation as soon as possible.

1.1 Supported Kernels

Oracle Linux 6 Update 8 ships with three sets of kernel packages:

  • Unbreakable Enterprise Kernel Release 4 (4.1.12-37.3.1.el6uek) for x86-64

  • Unbreakable Enterprise Kernel Release 2 (kernel-uek-2.6.39-400.278.2.el6uek) for i386

  • Red Hat Compatible Kernel (kernel-2.6.32-642.el6) for i386 and x86-64

By default, both the Unbreakable Enterprise Kernel and the Red Hat Compatible Kernel for the specific architecture (i386 or x86-64) are installed and the system boots the Unbreakable Enterprise Kernel.

The ISO image for Oracle Linux 6 Update 8 for i386 includes the Red Hat Compatible Kernel and the Unbreakable Enterprise Kernel Release 2 but not the Unbreakable Enterprise Kernel Release 4, which does not support i386.

The ISO image for Oracle Linux 6 Update 8 for x86-64 includes the Red Hat Compatible Kernel and the Unbreakable Enterprise Kernel Release 4 Update 1 but not the Unbreakable Enterprise Kernel Release 2. Notably, the Unbreakable Enterprise Kernel Release 4 replaces the Unbreakable Enterprise Kernel Release 3 that was provided on the previous ISO. You are still able to run Oracle Linux 6 Update 8 using the latest Unbreakable Enterprise Kernel Release 3 version.

To make your system boot the Red Hat Compatible Kernel by default:

  1. Edit /etc/grub.conf and change the value of the default parameter to indicate the Red Hat Compatible Kernel. (Each entry for a bootable kernel in the file starts with a title definition. The entries are effectively numbered from 0 upwards, where 0 corresponds to the first entry in the file, 1 to the second entry, and so on. To view the GRUB manual, use the info grub command.)

  2. Edit /etc/sysconfig/kernel and change the setting for the default kernel package type from DEFAULTKERNEL=kernel-uek to DEFAULTKERNEL=kernel.