Oracle Linux 5.6 Release Notes

Updated June 2011


This document covers the following topics regarding Oracle Linux 5.6.

For the latest updates please refer to the online version of release notes available at:

NOTE: An upgrade of Oracle Linux from a beta release is not supported. Further, an in-place upgrade between major versions of Oracle Linux is not supported. Oracle does not recommend an upgrade from earlier major versions of Oracle Linux even though anaconda provides an option to do this upgrade. A fresh installation is strongly recommended rather than a system upgrade between major versions.

Changes from the Upstream Release

The following RPMs are modified from the upstream release. All changes are trademark and look/feel related unless otherwise noted below under the specific RPM.

The following packages have been removed

The following documentation packages are removed

New Packages added in this release

The following packages were added upstream for this release (5.6) which were not in the previous update release (5.5)

New Packages added by Oracle

The following packages have been added to the release

Kernel and Driver Updates

Oracle Linux 5.6 ships with following three sets of kernel packages

Note:Both Unbreakable Enterprise kernel and Red Hat compatible kernel are installed on 64 bit (x86_64) platform and the system boots with Unbreakable Enterprise kernel by default. If needed /etc/grub.conf can be modifed to make the system boot with Red Hat compatible kernel by default.

Red Hat Compatible Kernel

This section covers significant changes in the Red Hat compatible kernel in this release.This kernel is the default kernel when you install Oracle Linux on a 32 bit platform.

Fixes/Additions from the upstream distribution provider

Driver Updates

Support for the following drivers is added to the installer in this release:

Network Storage

Red Hat Compatible Kernel with Bug Fixes by Oracle

This is the Red Hat compatible kernel with critical bug fixes produced by Oracle.

Bug Fixes


This kernel needs to be manually installed. Use following steps to install this kernel

  1. Mount Oracle Linux 5.6 DVD
  2. Copy the rpms from mount_point/Server/oracle_updated to your system
  3. Install required kernel using the rpm command, e.g.
    # rpm -ihv kernel-2.6.18-

Unbreakable Enterprise Kernel ( x86_64 architecture only)


The Unbreakable Enterprise Kernel is based on the upstream kernel 2.6.32-21 stable source tree with additional performance improvements, including:

The Unbreakable Enterprise Kernel is available for the x86_64 architecture and is the default kernel after installation.

Note: Starting this release Unbreakable Enterprise Kernel package name has changed from kernel to kernel-uek.

New Features

Known Issues

  1. Hardware virtualized guest with kernel-uek-2.6.32-100.35.1.el5uek and higher
  2. Unbreakable Enterprise Kernel version kernel-uek-2.6.32-100.35.1 adds support for paravirtualized drivers in a harware virtualized guest on Oracle VM. Starting this kernel version hardware virtualized guests which are not configured to use paravirtualized drivers will need an additional kernel boot parameter "xen_emul_unplug=never" in /etc/grub.conf:
    kernel /vmlinuz-2.6.32-100.35.1.el5uek ro root=/dev/VolGroup00/LogVol00  xen_emul_unplug=never 
    With kernel-uek-2.6.32-100.35.1 and higher, the default is to present only paravirtualized drivers when running in a hardware virtualized guest on Oracle VM. Adding this kernel boot parameter makes the kernel also present the emulated drivers as it did before (e.g. the 8139cp network driver may no longer load if this parameter is not set).

    Older version of Unbreakable Enterprise Kernel do not have support for hardware virtualized guest that uses paravirtualized drivers (PVHVM).
  3. kernel-uek-headers on Unbreakable Linux Network (ULN)
  4. Package kernel-uek-headers is available in "Enterprise Linux 5 Add ons (x86_64)" (el5_x86_64_addons) channel on ULN. To install kernel-uek-headers subscribe to el5_x86_64_addons channel and install kernel-uek-headers using following command
      # up2date kernel-uek-headers
      # yum install kernel-uek-headers
    To replace kernel-uek-headers with kernel-headers
  5. Console appears to hang while booting on certain systems (orabug 10094052)
  6. On some hardware, the console may appear to hang during the boot process after starting udev. But the system does boot up properly and is accessible. A workaround to this problem is to add "nomodeset" as a kernel boot parameter in /etc/grub.conf:
      kernel /vmlinuz-2.6.32-100.0.10.el5.x86_64 ro root=/dev/sd0 nomodeset 
  7. NFS: Error message displayed while mounting an NFS filesystem (orabug 10070721)
  8. The following error may be encountered while mounting an NFS filesystem:
    This is an informative message and can be ignored
  9. Serial console not working for a paravirtualized guest (orabug 10059184)
  10. Please use the following steps to configure the serial console in a paravirtualized guest (PV) using the Unbreakable Enterprise kernel (updates are in the guest):
    1. change the kernel boot parameter 'console=xvc0' to 'console=hvc0' in the /etc/grub.conf:
    2.     kernel /vmlinuz-2.6.32-100.0.19.el5 ro root=/dev/sd0 console=tty0 console=hvc0
    3. add an 'hvc0' entry to /etc/inittab:
    4.     co:2345:respawn:/sbin/agetty hvc0 9600 vt100-nav
    5. add an 'hvc0' entry to /etc/securetty
  11. Unable to start X (orabug 10056679)
  12. On some hardware startup of X environment may fail after upgrading to Unbreakable Enterprise Kernel with following Error:
        Fatal server error:
        Cannot run in framebuffer mode. Please specify busIDs for all
        framebuffer devices.
    To workaround this issue reconfigure X using command "X -configure" and use generated configuration file to start X environment.
  13. Higher memory is required for crashkernel option
  14. With unbreakable Enterprise Kernel higher memory setting is required for crashkernel option in /etc/grub.conf file. Booting with crashkernel=128M@16M will result in following error:
        crashkernel reservation failed - memory is in use
    Minimum value for crashkernel option is 128M@32M. Based on the system configuration a higher value may be required. If kdump service loading fails increase the second value (32M). If the system hangs or crashes with out of memory during dumping core increase the first value (128M)
  15. Unbreakable Enterprise Kernel does not recognise /dev/hd* devices (orabug 10055889)
  16. Unbreakable Enterprise kernel does not recognise /dev/hd* entries in hardware virtualized guests. Make sure to use lables for all /dev/hd* devices in /etc/fstab before updating the kernel. This kernel package will not install if / or /boot partition is using devices like /dev/hd* in /etc/fstab.

Technology Preview Features

The following Technology Preview features are currently not supported under Oracle Linux 5 and may not be functionally complete.

These features are not suitable for production use. However, these features are included to provide the feature with wider exposure.

Known Issues

  1. The versions of kpartx and device-mapper-multipath installed by default, while required for the Unbreakable Enterprise Kernel, do not work with the Red Hat compatible kernel.

    The instructions for installing the versions of kpartx and device-mapper-multipath to go with the Red Hat compatible kernel via ULN are as follows:

  2. pirut and system-config-packages cannot be used to manage, install, and uninstall software packages. Follow the steps below to resolve the issue

  3. Following packages can not co-exists due to file conflict

  4. If updating from Oracle Linux 5 GA or RHEL 5 GA using up2date, you may encounter the following error:
      Unresolvable chain of dependencies:
      xen-3.0.3-64.el5    requires xen-hypervisor-abi = 3.1
    This happens because a kernel-xen package update is needed by the xen package, but 'kernel*' is part of the up2date pkgSkipList. To get around this, add 'xen;xen-devel;' to the the pkgSkipList line in /etc/sysconfig/rhn/up2date and then run up2date. You can update the xen and kernel-xen packages together later via 'up2date --force xen kernel-xen'.

Oracle Linux Support

Oracle Linux offers an option to keep your operating system up to date with latest operating system patches using up2date. To access Linux updates via Unbreakable Linux Network, you must purchase a Linux support subscription.For more information please visit

Note: Prior to using up2date, import the RPM-GPG-KEY for Oracle Linux:

rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY