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:
http://oss.oracle.com/el5/docs/
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.
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
The following packages were added upstream for this release (5.6) which were not in the previous update release (5.5)
The following packages have been added to the release
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.
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.
Support for the following drivers is added to the installer in this release:
This is the Red Hat compatible kernel with critical bug fixes produced by Oracle.
This kernel needs to be manually installed. Use following steps to install this 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 and is the default kernel after installation.
Note: Starting this release Unbreakable Enterprise Kernel package name has changed from kernel to kernel-uek.
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 the OCFS2 1.6 kernel module. New features include:For more details, see the OCFS2 1.6 User's Guide
- JBD2 support
- Extended attributes
- POSIX ACLs
- Security attributes
- Metadata checksums
- Indexed directories
- REFLINKs
TCG can track and group processes into user-defined cgroups so that the operating system can treat them as whole and perform scheduling, accounting, and resource allocation accordingly. For example, using TCG, you can associate a set of CPU cores and memory nodes to a group of processes that make up an application or a group of applications. This enables subsetting larger systems, more fine grained control over CPU and memory, and isolation of applications.
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:/sys/block/xxx/queue/rotationalWhere 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. For example, the following will turn IO affinity on:echo 1> /sys/block/sda/queue/rq_affinity
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. To enable receive packet steering for the interface xxx, place a CPU mask into/sys/class/net/xxx/queues/rx-0/rps_cpusThe cpu mask takes the same form as the masks for the taskset command. For example:echo 0x55> /sys/class/net/eth0/queues/rx-0/rps_cpus
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.
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=neverWith 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).
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 or # yum install kernel-uek-headersTo replace kernel-uek-headers with kernel-headers
- make sure system is not subscribed to el5_x86_64_addons channel
- remove package kernel-uek-headers using following command
rpm -ev --nodeps kernel-uek-headers- Install kernel-headers package using following command
# up2date kernel-headers or # yum install kernel-headers
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
The following error may be encountered while mounting an NFS filesystem:
"SVC: FAILED TO REGISTER LOCKDV1 RPC SERVICE (ERRNO 97)."
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):.
- 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- add an 'hvc0' entry to /etc/inittab:
co:2345:respawn:/sbin/agetty hvc0 9600 vt100-nav- 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 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)
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.
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.
# up2date --get kpartx-0.4.7-42.el5 device-mapper-multipath-0.4.7-42.el5RPMs will be downloaded to /var/spool/up2date
# multipath -F
# service multipathd stop Stopping multipathd daemon: [ OK ]
# rpm -Uvh --force kpartx-0.4.7-42.el5.x86_64.rpm device-mapper-multipath-0.4.7-42.el5.x86_64.rpm Preparing... ########################################### [100%] 1:kpartx ########################################### [ 50%] 2:device-mapper-multipathwarning: /etc/multipath.conf created as /etc/multipath.conf.rpmnew warning: /etc/udev/rules.d/40-multipath.rules saved as /etc/udev/rules.d/40-multipath.rules.rpmsave ########################################### [100%] # rpm -e device-mapper-multipath-libs
# service multipathd start Starting multipathd daemon: [ OK ]
device-mapper-multipath*;kpartx*;
Command for mounting the DVD media inserted in /dev/cdrom # mount -r -o loop -t iso9660 /dev/cdrom /mnt
Command to mount iso image file # mount -o loop/mnt
[dvd]
name=OEL5DVD
baseurl=file:///mnt/Server
enabled=1
gpgcheck=1
gpgkey=file:///mnt/RPM-GPG-KEY file:///mnt/RPM-GPG-KEY-oracle
# yum clean all
# yum update
Unresolvable chain of dependencies: xen-3.0.3-64.el5 requires xen-hypervisor-abi = 3.1This 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 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 http://linux.oracle.com
Note: Prior to using up2date, import the RPM-GPG-KEY for Oracle Linux:
rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY