Oracle Linux  Release Notes

  (Release 5.5)

Updated Sept. 2010


 This document covers the following topics regarding Oracle  Linux 5.5.

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

:  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 do to 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.

Path of the Distribution changed from RedHat to Enterprise on the install CDs.
Additional kernel containing additional fixes by Oracle (see  Kernel and Driver Update section)
ocfs2 related fix.

The following packages are removed

           Replaced by oracle-logos
           Replaced by enterprise-release
           Replaced by enterprise-release-notes-5Server
              Replaced by up2date               Replaced by up2date The following documentation packages are removed

New Packages added in this release

       The following packages were added upstream for this release (5.5) which were not in the previous update release  (5.4)

New Packages added by Oracle

Oracle Linux has these additional packages

Kernel  and Driver Updates

Oracle Linux 5.5 ships with following three sets of kernel packages


Unmodified Kernel

 This section covers  significant changes in the default kernel in this release.

Fixes/Additions from the upstream distribution provider

Driver Updates



Optional Kernel with Bug Fixes by Oracle

This kernel includes bug fixes added by Oracle on top of unmodified kernel.

Bug Fixes


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

1. mount Oracle  Linux 5.5 CD 1 or DVD

2. copy the rpms from <mount_point>/Server/oracle_updated to your system

3. install the required  kernel using the rpm command, e.g.
             # rpm -ihv kernel-2.6.18-

Unbreakable Enterprise Kernel


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.

New Features

The Unbreakable Enterprise Kernel  is tickless. In the tickless kernel, timer interrupts are performed on demand rather than at a predetermined frequency. This allows CPUs to stay in a low power state when the system is idle, reducing overall power consumption

OFED implements Remote Direct Memory Access (RDMA) and kernel bypass mechanisms to deliver high-efficiency computing, wire-speed messaging, ultra-low microsecond latencies and fast I/O for servers, block storage and file systems.

The Unbreakable Enterprise Kernel  includes OCFS2 1.6 kernel module. Following are the new features included:


The performance counter subsystem keeps track of hardware and software events without affecting performance and enables you to do tracing and performance analysis. includes the a tool called perf for analysis.

Latency can be defined as follows: an applications wants to run and execute code, but is blocked by the kernel because some required resource is not available. LatencyTOP is a Linux tool for software developers (both kernel and userspace), aimed at identifying where system latency occurs, and what kind of operation or action is causing the latency to happen. By identifying this, developers can then change the code to avoid the worst latency hiccups.

The kernel block layer will detect devices that claim to be fast, solid state storage and tune itself accordingly. The result of this detection can be found in:


Where xxx is the block device. Echoing a 0 or a 1 into this file will force the value to off or on. When assuming a device is an SSD, the block layer will try harder to immediately dispatch the IO to the device.

IO affinity ensures processing of a completed IO is handled by the same CPU that initiated the IO. It can have a fairly large impact on performance, especially on large NUMA machines.

IO affinity is turned on by default, but it can be controlled via the tunable in /sys/block/xxx/queue/rq_affinity

example: echo 1> /sys/block/sda/queue/rq_affinity will turn it on.

RPS distributes the load of received packet processing across multiple CPUs. This solution allows protocol processing (e.g. IP and TCP) to be performed on packets in parallel. This removes a bottleneck when a single core is saturated processing network interrupts.

fallocate() is a new system call which will allow applications to preallocate space to any file(s) in a file system. Applications can get a guarantee of space for particular file(s) - even if later the system becomes full. Using this method of allocation can dramatically speed up the creation of large files such as those used for virtual machine images.


The Unbreakable Enterprise Kernel and other packages are available on the Unbreakable Linux Network (ULN). Login to the Unbreakable Linux Network(ULN) and subscribe to the Oracle Linux 5 Latest channel to get updates to the Unbreakable Enterprise Kernel. The initial set of packages are also available on

Installation steps

1. Install the Unbreakable Enterprise Kernel and dependent packages (required):

       # up2date kernel

2. Optional but recommended.

     Install additonal packages needed for Oracle Database Installation:

       # up2date oracle-validated


      Install additional recommended packages (superset of packages installed by oracle-validated):

        # up2date oracle-linux


         Note: If the ofa kernel module is needed, install this module using the following steps:

   Upgrade to the Unbreakable Enterprise Kernel using one of the methods above
   Reboot your system and check that you are booting the Unbreakable Enterprise Kernel (uname –r should say 2.6.32-100.0.19.el5)

                  # update ofa-`uname -r`

      List of packages included  

Known Issues

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 

Currently, this configuration does not boot properly. Please do not install this kernel in a hardware virtualized guest that uses paravirtualized drivers (PVHVM).  Installing the kernel in a hardware virtualized guest without paravirtualized drivers (HVM) or in a paravirtualized guest (PV) works without problems.

The following error may be encountered while mounting an NFS filesystem:


This is an informative message and can be ignored

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:
     kernel /vmlinuz-2.6.32-100.0.19.el5 ro root=/dev/sd0 console=tty0 console=hvc0
2. add an 'hvc0' entry to /etc/inittab:
     co:2345:respawn:/sbin/agetty hvc0 9600 vt100-nav
3. add an 'hvc0' entry to /etc/securetty.

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.

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 higher value may be required. If kdump service loading fails increase the second value (32M). If system hangs or crashes with out of memory during dumping core increase the first value (128M)

The path checker fails to recognise the restored storage path, thus fail to restore the device-mapper multipaths and shows status as faulty. Need to restart mutlipathd for path checker to recognise restored storage paths.

This error at boot can be safely ignored. If this error is encountered at runtime (while attempting to set the hardware clock) please install the provided util-linux RPM.

Unbreakable Enterprise kernel does not recognise /dev/hd* entries in hardware virtualized guests. Make sure to use sables 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. pirut and system-config-packages  cannot be used to manage, install, and uninstall software packages. Follow the steps describe below to resolve the issue

Use the following command for mounting the DVD media inserted in /dev/cdrom

# mount -r -o loop -t  iso9660 /dev/cdrom /mnt

Use following command to mount iso image file

# mount -o loop <iso image file name>  /mnt

gpgkey=file:///mnt/RPM-GPG-KEY file:///mnt/RPM-GPG-KEY-oracle

# yum clean all
# yum update

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

3. 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'.

Unbreakable Linux Support

Oracle  Linux offers an option to keep your operating system up to date with latest operating system patches using up2date.  To be able to  use this option you need to have Unbreakable Linux  Support. 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