[El-errata] Oracle Linux Release 6

Errata Announcements for Oracle Linux el-errata at oss.oracle.com
Fri Feb 11 15:30:11 PST 2011

Oracle is pleased to announce the general availability of Oracle Linux 6 for x86 (32 bit) and x86_64 (64 bit) architectures.

Oracle Linux 6 includes many new features, including:

     * ext4 filesystem
            The ext4 filesystem is installed by default.

     * XFS
            Oracle Linux 6 includes XFS as an optional filesystem.

     * ftrace
            Ftrace is a tracing framework for analyzing performance and
            latency in the kernel.

     * Performance Counters for Linux (PCL) and perf
            The performance counter subsystem keeps track of hardware and
            software events without affecting performance and enables you
            to do tracing and performance analysis. Included is a tool
            called perf for analysis.

     * Powertop
            Powertop is a new user space tool that helps you reduce server
            power usage by identifying power hungry processes and by
            providing recommendations to lower power consumption.

     * Latencytop
            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.

     * Yum-only access to Unbreakable Linux Network (ULN)
            Oracle Linux 6 not longer contains up2date for access to
            Unbreakable Linux Network. Instead packages are managed using
            Yum. To register with ULN, use the following command:


Oracle Linux 6 ships with two sets of kernel packages:

      * Unbreakable Enterprise Kernel [kernel-uek-2.6.32-100.28.5.el6]
            o Only available on the x86_64 (64 bit) platform
            o Installed and booted by default
      * Red Hat compatible Kernel [kernel-2.6.32-71.el6]
            o Installed by default

Unbreakable Enterprise Kernel (x86_64 architecture only)

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

     * improved IRQ balancing
     * reduced lock contention across the kernel
     * improved network I/O via receive packet steering and RDS improvements
     * improved virtual memory performance

New Features

     * OpenFabrics Enterprise Distribution (OFED) 1.5.1
            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.

     * OCFS2 1.6
            The Unbreakable Enterprise Kernel includes the OCFS2 1.6 kernel
            module. New features include:
              o JBD2 support
              o Extended attributes
              o POSIX ACLs
              o Security attributes
              o Metadata checksums
              o Indexed directories
              o REFLINKs
      For more details, see the OCFS2 1.6 User's Guide

     * DIF/DIX support
            The Linux data integrity framework (DIF) enables applications or
            kernel subsystems to attach metadata to I/O operations, allowing
            devices that support DIF to verify the integrity before passing them
            further down the stack and physically committing them to disk. Data
            Integrity Extensions or DIX is a hardware feature that enables
            exchange of protection metadata between host operating system and

     * Tickless kernel
            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

     * Task Control Groups (TCG)
            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 makeup an application or a group of applications.
            This enables subsetting larger systems, more fine grained control
            over CPU and memory, and isolation of applications.

     * Performance Counters for Linux (PCL)
            The performance counter subsystem keeps track of hardware and
            software events without affecting performance and enables you to do
            tracing and performance analysis. Included is a tool called perf for

     * SSD Detection
            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

     * IO affinity
            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

     * Receive packet steering (RPS)
           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


           The 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()
           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.

For more information, please refer to the online release notes available at:


Software Accessibility

All packages are available on the Unbreakable Linux Network (http://linux.oracle.com).

Installable binary and source ISO images are available on eDelivery (http://edelivery.oracle.com/linux).

Thank you.


The Oracle Linux Team

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