Red Hat Enterprise Linux 5.4

                             Release Notes

Release Notes for all architectures.

  Red Hat Engineering Content Services
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        Abstract

   1st July 2009
   This document details the Release Notes Red Hat Enterprise Linux
   5.4.

   ------------------------------------------------------------------

   1. Virtualization Updates

   2. Clustering Updates

                2.1. Fencing Improvements

   3. Networking Updates

   4. Filesystems Updates

   5. Desktop Updates

                5.1. Advanced Linux Sound Architecture

                5.2. Graphics Drivers

                5.3. Laptop Support

   6. Tools Updates

   7. Architecture Specific Support

                7.1. i386

                7.2. x86_64

                7.3. PPC

                7.4. s390

   8. Kernel Updates

                8.1. General Kernel Feature Support

                8.2. General Platform Support

                8.3. Driver Updates

   9. Technology Previews

   A. Revision History

   This document contains the Release Notes for the Red Hat
   Enterprise Linux 5.4 (kernel-2.6.18-154.EL) family of products
   including:

     * Red Hat Enterprise Linux 5 Advanced Platform for x86,
       AMD64/Intel® 64, Itanium Processor Family, System p and System
       z
     * Red Hat Enterprise Linux 5 Server for x86, AMD64/Intel® 64,
       Itanium Processor Family, System p and System z
     * Red Hat Enterprise Linux 5 Desktop for x86 and AMD64/Intel®

   The Release Notes provide high level coverage of the improvements
   and additions that have been implemented in Red Hat Enterprise
   Linux 5.4.

Note

   The format of the Release Documentation has changed for Red Hat
   Enterprise Linux 5.4. The Release Notes now contain an overview of
   important feature updates, bugfixes and Technology Previews. The
   new Technical Notes document details all updated packages, known
   issues and Technology Previews.

1. Virtualization Updates

   Red Hat Enterprise Linux 5.4 now includes full support for the
   Kernel-based Virtual Machine (KVM) hypervisor on x86_64 based
   architectures. KVM is integrated into the Linux kernel, providing
   a virtualization platform that takes advantage of the stability,
   features, and hardware support inherent in Red Hat Enterprise
   Linux. Virtualization using the KVM hypervisor is supported on
   wide variety of guest operating systems, including:

     * Red Hat Enterprise Linux 3
     * Red Hat Enterprise Linux 4
     * Red Hat Enterprise Linux 5
     * Windows XP
     * Windows Server 2003
     * Windows Server 2008

Important

   Xen based virtualization is fully supported. However, Xen-based
   virtualization requires a different version of the kernel to
   function. The KVM hypervisor can only be used with the regular
   (non-Xen) kernel.

Warning

   While Xen and KVM may be installed on the same system, the default
   networking configuration for these are different. Users are
   strongly recommended to only install one hypervisor on a system.

Note

   Xen is the default hypervisor that is shipped with Red Hat
   Enterprise Linux. As such all configuration defaults are tailored
   for use with the Xen hypervisor. For details on configuring a
   system for KVM, please refer to the Virtualization Guide.
   Virtualization using KVM allows both 32-bit and 64-bit versions of
   guest operating systems to be run without modification.
   Paravirtualized disk and network drivers have also been included
   in Red Hat Enterprise Linux 5.4 for enhanced I/O performance. All
   the libvirt based tools (i.e. virsh, virt-install and
   virt-manager) have also been updated with added support for KVM.
   USB passthrough with the KVM hypervisor is considered to be a
   Technology Preview for the 5.4 release.
   With resolution of various issues such as: save/restore, live
   migration and core dumps, Xen based 32 bit paravirtualized guests
   on x86_64 hosts are no longer classed as a Technology Preview, and
   are fully supported on Red Hat Enterprise Linux 5.4.
   the etherboot package has been added in this update, providing the
   capability to boot guest virtual machines using the Preboot
   eXecution Environment (PXE). This process occurs before the OS is
   loaded and sometimes the OS has no knowledge that it was booted
   through PXE. Support for etherboot is limited to usage in the KVM
   context.
   The qspice packages have been added to Red Hat Enterprise Linux
   5.4 to support the spice protocol in qemu-kvm based virtual
   machines. qspice contains both client, server and web browser
   plugin components. However, only the qspice server in the
   qspice-libs package is fully supported. The qspice client
   (supplied by the qspice package) and qspice mozilla plugin
   (supplied by the qspice-mozilla package) are both included as
   Technology Previews. The qspice-libs package contains the server
   implementation that is used in conjunction with qemu-kvm and as
   such is fully supported. However, in Red Hat Enterprise Linux 5.4
   there is no libvirt support for the spice protocol; the only
   supported use of spice in Red Hat Enterprise Linux 5.4 is through
   the use of the Red Hat Enterprise Virtualization product.

2. Clustering Updates

   Clusters are multiple computers (nodes) working in concert to
   increase reliability, scalability, and availability to critical
   production services.
   All updates to clustering in Red Hat Enterprise Linux 5.4 are
   detailed in the Technical Notes. Further information on clustering
   in Red Hat Enterprise Linux is available in the Cluster Suite
   Overview and the Cluster Administration documents.
   Cluster Suite tools have been upgraded to support automatic
   hypervisor detection. However, running the cluster suite in
   conjunction with KVM hypervisor is considered to be a Technology
   Preview.
   OpenAIS now provides broadcast network communication in addition
   to multicast. This functionality is considered Technology Preview
   for standalone usage of OpenAIS and for usage with the Cluster
   Suite. Note, however, that the functionality for configuring
   OpenAIS to use broadcast is not integrated into the cluster
   management tools and must be configured manually.

Note

   SELinux in Enforcing mode is not supported with the Cluster Suite;
   Permissive or Disabled modes must be used. Using Cluster Suite on
   bare metal PPC systems is not supported. Guests running Cluster
   Suite on VMWare ESX hosts and using fence_vmware is considered a
   Technology Preview. Running Cluster Suite in guests on VMWare ESX
   hosts that are managed by Virtual Center is not supported.
   Mixed architecture clusters using Cluster Suite are not supported.
   All Nodes in the cluster must be of the same architecture. For the
   purposes of Cluster Suite, x86_64, x86 and ia64 are considered to
   be the same architecture, so running clusters with combinations of
   these architectures is supported.

  2.1. Fencing Improvements

   Fencing is the disconnection of a node from the cluster's shared
   storage. Fencing cuts off I/O from shared storage, thus ensuring
   data integrity.
   In Red Hat Enterprise Linux 5.4, fencing support on Power Systems
   has been added, as a Technology Preview, for IBM Logical Partition
   (LPAR) instances that are managed using the Hardware Management
   Console (HMC) (BZ#485700). Fencing support has also been added, as
   a Technology Preview for Cisco MDS 9124 & Cisco MDS 9134
   Multilayer Fabric Switches (BZ#480836).
   The fence_virsh fence agent is provided in this release of Red Hat
   Enterprise Linux as a Technology Preview. fence_virsh provides the
   ability for one guest (running as a domU) to fence another using
   the libvirt protocol. However, as fence_virsh is not integrated
   with cluster-suite it is not supported as a fence agent in that
   environment.
   Additionally, the following new articles on fencing have been
   published on the Red Hat Knowledge Base:

     * SCSI Fencing (Persistent Reservations) with Red Hat Enterprise
       Linux 5 Advanced Platform Cluster Suite:
       http://kbase.redhat.com/faq/docs/DOC-17809
     * Using fence_vmware with Red Hat Enterprise Linux 5 Advanced
       Platform Cluster Suite:
       http://kbase.redhat.com/faq/docs/DOC-17345

3. Networking Updates

   With this update, Generic Receive Offload (GRO) support has been
   implemented in both the kernel and the userspace application,
   ethtool.((BZ#499347)) The GRO system increases the performance of
   inbound network connections by reducing the amount of processing
   done by the Central Processing Unit (CPU). GRO implements the same
   technique as the Large Receive Offload (LRO) system, but can be
   applied to a wider range of transport layer protocols. GRO support
   has also been added to a several network device drivers, including
   the igb driver for Intel® Gigabit Ethernet Adapters and the ixgbe
   driver for Intel 10 Gigabit PCI Express network devices.
   The Netfilter framework (the portion of the kernel resposible for
   network packet filtering) has been updated with added support for
   Differentiated Services Code Point (DSCP) values
   the bind (Berkeley Internet Name Domain) package provides an
   implementation of the DNS (Domain Name System) protocols.
   Previously, bind did not offer a mechanism to easily distinguish
   between requests that will receive authoritative and
   non-authoritative replies. Consequently, an incorrectly configured
   server may have replied to requests that should have been denied.
   With this update, bind has been updated, providing the new option
   allow-query-cache that controls access to non-authoritative data
   on a server (for example: cached recursive results and root zone
   hits). (BZ#483708)

4. Filesystems Updates

   In the 5.4 update, several significant additions have been made to
   file systems support. Base Red Hat Enterprise Linux now includes
   the Filesystem in Userspace (FUSE) kernel modules and user space
   utilities, allowing users to install and run their own FUSE file
   systems on an unmodified Red Hat Enterprise Linux kernel
   (BZ#457975). Support for the XFS file system has also been added
   to the kernel as a Technology Preview (BZ#470845). The FIEMAP
   input/output control (ioctl) interface has been implemented,
   allowing the physical layout of files to be mapped efficiently.
   The FIEMAP ioctl can be used by applications to check for
   fragmentation of a specific file or to create an optimized copy of
   a sparsely allocated file (BZ#296951).
   Additionally, the Common Internet File System (CIFS) has been
   updated in the kernel (BZ#465143). The ext4 file system (included
   in Red Hat Enterprise Linux as a Technology Preview) has also been
   updated (BZ#485315).
   In Red Hat Enterprise Linux 5.4, the use of the Global File System
   2 (GFS2) as a single server file system (i.e. not in a clustered
   environment) is deprecated. Users of GFS2 that do not need high
   availability clustering are encouraged to look at migrating to
   other file systems like the ext3 or xfs offerings. The xfs file
   system is specifically targeted at very large file systems (16 TB
   and above). Existing users will continue to be supported.
   The required semantics indicate that a process which completes a
   stat, write, stat, should see a different mtime (time of last
   modification) on the file in the results from the second stat call
   compared to the mtime in the results from the first stat call.
   File times in NFS are maintained strictly by the server, so the
   file mtime will not be updated until the data has been transmitted
   to the server via the WRITE NFS protocol operation. Simply copying
   data into the pagecache is not sufficient to cause the mtime to be
   updated. This is one place where NFS differs from local file
   systems. Therefore, an NFS filesystem which is under a heavy write
   workload may result in stat calls having a high
   latency.(BZ#469848)
   The ext4 filesystem Technology Preview has been refreshed with
   updated userspace tools. Ext4 is an incremental improvement on the
   ext3 file system developed by Red Hat and the Linux community.

Note

   In previous versions of Red Hat Enterprise Linux utilizing the
   ext4 Technology Preview, ext4 filesystems were labeled as ext4dev.
   With this update, ext4 filesystems are now tagged as ext4.
   samba3x and ctdb are provided as a Technology Preview on the
   x86_64 platform. Samba3x package provides Samba 3.3 and ctdb
   provide a clustered TDB backend. Running samba3x and ctdb on a set
   of cluster nodes with GFS file system will allow the export of a
   clustered CIFS filesystem. These components are provided in an
   alternate child channel since they conflict with files installed
   from the samba package in the Client and Server groups

5. Desktop Updates

  5.1. Advanced Linux Sound Architecture

   In Red Hat Enterprise Linux 5.4, the Advanced Linux Sound
   Architecture (ALSA) has been updated — providing enhanced support
   for High Definition Audio (HDA).

  5.2. Graphics Drivers

   The ati driver for ATI video devices has been updated.
   The i810 and intel drivers for Intel integrated display devices
   have been updated.
   The mga driver for Matrox video devices has been updated.
   The nv driver for nVidia video devices has been updated.

  5.3. Laptop Support

   Previously, when undocking and docking some laptops with docking
   stations containing integrated CD/DVD drives, the drive would no
   longer be recognized. The system would need to be rebooted for the
   drive to be accessible. With this update, the ACPI docking drivers
   have been updated in the kernel, resolving this issue.
   (BZ#485181).

6. Tools Updates

     * SystemTap is now fully supported, and has been re-based to the
       latest upstream version. This update features improved
       user-space probing through shared libraries, experimental
       DWARF unwinding, and a new <sys/sdt.h> header file which
       provides dtrace-compatible markers.
       This re-base also enhances support for debuginfo-less
       operations. Typecasting (through the @cast operator) is now
       supported, along with kernel tracepoint probing. Several
       'kprobe.*' probe bugs that hampered debuginfo-less operations
       are also now resolved.
       SystemTap also features several documentation improvements. A
       new '3stap' feature provides users with useful man pages on
       most SystemTap probes and functions. The systemtap-testsuite
       package also features a larger library of sample scripts.
       For more information about the SystemTap re-base, please refer
       to the SystemTap section Package Updates chapter of the
       Technical Notes.
     * Systemtap tracepoints are placed in important sections of the
       kernel, allowing system administrators to analyze the
       performance of, and debug portions of code. In Red Hat
       Enterprise Linux 5.4, tracepoints have been added to the
       following sections of the kernel subsystem as a Technology
       Preview:

          * Memory Management (mm) (BZ#493444)
          * Block Device I/O (blktrace)(Bugzilla #493454)
          * Network File System (NFS) (BZ#499008)
          * Page Cache and Networking stacks (BZ#475719)
          * Scheduler (BZ#497414)

     * The Gnu Compiler Collection version 4.4 (GCC4.4) is now
       included in this release as a Technology Preview. This
       collection of compilers include C, C++, and Fortran compilers
       along with support libraries.
     * glibc new MALLOC behaviour: The upstream glibc has been
       changed recently to enable higher scalability across many
       sockets and cores. This is done by assigning threads their own
       memory pools and by avoiding locking in some situations. The
       amount of additional memory used for the memory pools (if any)
       can be controlled using the environment variables
       MALLOC_ARENA_TEST and MALLOC_ARENA_MAX.
       MALLOC_ARENA_TEST specifies that a test for the number of
       cores is performed once the number of memory pools reaches
       this value. MALLOC_ARENA_MAX sets the maximum number of memory
       pools used, regardless of the number of cores.
       The glibc in the RHEL 5.4 release has this functionality
       integrated as a Technology Preview of the upstream malloc. To
       enable the per-thread memory pools the environment variable
       MALLOC_PER_THREAD needs to be set in the environment. This
       environment variable will become obsolete when this new malloc
       behaviour becomes default in future releases. Users
       experiencing contention for the malloc resources could try
       enabling this option.

7. Architecture Specific Support

  7.1. i386

     * In a virtual environment, timekeeping for Red Hat Enterprise
       Linux 64-bit kernels can be problematic, since time is kept by
       counting timer interrupts. De- and re-scheduling the virtual
       machine can cause a delay in these interrupts, resulting in a
       timekeeping discrepancy. This kernel release reconfigures the
       timekeeping algorithm to keep time based on a time-elapsed
       counter. (Bugzilla #463573)
     * It was found that, if their stacks exceed the combined size of
       ~4GB, 64-bit threaded applications slowed down drastically in
       pthread_create(). This is because glibc uses MAP_32BIT to
       allocate those stacks. As the use of MAP_32BIT is a legacy
       implementation, this update adds a new flag (MAP_STACK mmap)
       to the kernel to avoid constraining 64-bit applications.
       (Bugzilla #459321)
     * The update includes a feature bit that encourages TSCs to keep
       running in deep-C states. This bit NONSTOP_TSC acts in
       conjunction with CONSTANT_TSC. CONSTANT_TSC indicates that the
       TSC runs at constant frequency irrespective of P/T- states,
       and NONSTOP_TSC indicates that TSC does not stop in deep
       C-states. (Bugzilla #474091)
     * This update includes a patch to include asm-x86_64 headers in
       kernel-devel packages built on or for i386, i486, i586 and
       i686 architectures. (Bugzilla #491775)
     * This update includes a fix to ensure that specifying
       memmap=X$Y as a boot parameter on i386 architectures yields a
       new BIOS map. (Bugzilla #464500)
     * This update adds a patch to correct a problem with the
       Non-Maskable Interrupt (NMI) that appeared in previous kernel
       releases. The problem appeared to affect various Intel
       processors and caused the system to report the NMI watchdog
       was 'stuck'. New parameters in the NMI code correct this
       issue. (Bugzilla #500892)
     * This release re-introduces PCI Domain support for HP xw9400
       and xw9300 systems. (Bugzilla #474891)
     * Functionality has been corrected to export module powernow-k8
       parameters to /sys/modules. This information was previously
       not exported.(Bugzilla #492010)

  7.2. x86_64

     * An optimization error was found in
       linux-2.6-misc-utrace-update.patch. When running 32-bit
       processes on a 64-bit machine systems didn't return ENOSYS on
       missing (out of table range) system calls. This kernel release
       includes a patch to correct this. (Bugzilla #481682)
     * Some cluster systems were found to boot with an unstable time
       source. It was determined that this was a result of kernel
       code not checking for a free performance counter (PERFCTR)
       when calibrating the TSC (Time Stamp Clock) during the boot
       process. This resulted, in a small percentage of cases, in the
       system defaulting to a busy PERFCTR and getting unreliable
       calibrations.
       A fix was implemented to correct this by ensuring the system
       checked for a free PERFCTR before defaulting (Bugzilla
       #467782). This fix, however, cannot satisfy all possible
       contingencies as it is possible that all PERFCTRs will be busy
       when required for TSC calibration. Another patch has been
       included to initiate a kernel panic in the unlikely event
       (fewer than 1% of cases) that this scenario occurs. (Bugzilla
       #472523).

  7.3. PPC

     * This kernel release includes various patches to update the
       spufs (Synergistic Processing Units file system) for Cell
       processors. (Bugzilla #475620)
     * An issue was identified wherein /proc/cpuinfo would list
       logical PVR Power7 processor architecture as "unknown" when
       show_cpuinfo() was run. This update adds a patch to have
       show_cpuinfo() identify Power7 architectures as Power6.
       (Bugzilla #486649)
     * This update includes several patches that are required to
       add/improve MSI-X (Message Signaled Interrupts) support on
       machines using System P processors. (Bugzilla #492580)
     * A patch has been added to this release to enable the
       functionality of the previously problematic power button on
       Cell Blades machines. (Bugzilla #475658)

  7.4. s390

   Red Hat Enterprise Linux introduces a wide range of new features
   for IBM System z machines, most notably:

     * Utilizing Named Saved Segments (NSS), the z/VM hypervisor
       makes operating system code in shared real memory pages
       available to z/VM guest virtual machines. With this update,
       multiple Red Hat Enterprise Linux guest operating systems on
       the z/VM can boot from the NSS and be run from a single copy
       of the Linux kernel in memory. (BZ#474646)
     * Device driver support has been added in this update for the
       new IBM System z PCI cryptography accelerators, utilizing the
       same interfaces as prior versions. (BZ#488496)
     * Red Hat Enterprise Linux 5.4 adds support for processor
       degradation, which allows processor speed to be reduced in
       some circumstances (i.e. system overheating). (BZ#474664) This
       new feature allows automation software to observe the machine
       state and act based on defined policies.

Note

       Processor degradation is supported on z990, z890 and later
       systems and is observed through SCLP system service event type
       4 event qualifier 3. STSI will report the new capacity of the
       processor in the file:
       /sys/devices/system/cpu/cpuN/capability.
     * Control Program Identification (CPI) descriptive data is used
       to identify individual systems on the Hardware Management
       Console (HMC). With this update, CPI data can now be
       associated with a Red Hat Enterprise Linux instance.
       (BZ#475820)
       For more information on CPI refer to the Device Drivers,
       Features, and Commands document
     * Fibre Channel Protocol (FCP) performance data can now be
       measured on Red Hat Enterprise Linux instances on the IBM
       System z platform. (BZ#475334) Metrics that are collected and
       reported on include:

          * Performance relevant data on stack components such as
            Linux devices, Small Computer System Interface (SCSI)
            Logical Unit Numbers (LUNs) and Host Bus Adapter (HBA)
            storage controller information.
          * Per stack component: current values of relevant
            measurements as throughput, utilization and other
            applicable measurements.
          * Statistical aggregations (minimum, maximum, averages and
            histogram) of data associated with I/O requests including
            size, latency per component and totals.

     * Support has been added to the kernel to issue EMC Symmetrix
       Control I/O. This update provides the ability to manage EMC
       Symmetrix storage arrays with Red Hat Enterprise Linux on the
       IBM System z platform. (BZ#461288)
     * A new feature has been implemented in the kernel to perform an
       Initial Program Load (IPL) on a Red Hat Enterprise Linux
       virtual machine immediately following a kernel panic and
       dump.(BZ#474688)
     * Hardware that supports the configuration topology facility
       passes the system CPU topology information to the scheduler,
       allowing it to make load balancing decisions. On machines
       where I/O interrupts are unevenly distributed, CPUs that are
       grouped together and get more I/O interrupts than others will
       tend to have a higher average load, creating performance
       issues in some cases.
       Previously, CPU topology support was enabled by default. With
       this update, CPU topology support is disabled by default, and
       the kernel parameter "topology=on" has been added to allow
       this feature to be enabled. (BZ#475797)
     * New kernel options can now be added using the IPL command
       without modifying the content of the CMS parmfile, allowing
       for temporary overwriting of kernel options that are already
       provided by the parmfile. The entire boot command line can be
       replaced with the VM parameter string, bypassing any kernel
       options from the parmfile. Furthermore, customers can create
       new Linux Named Saved Systems (NSS) on the CP/CMS command
       line. (BZ#475530)
     * The qeth driver has been updated with HiperSockets Layer3
       support for IPv6. (BZ#475572) For further details on this
       feature, refer to the "qeth device driver for OSA-Express
       (QDIO) and HiperSockets" chapter in IBM's "Device Drivers,
       Features, and Commands" book located at:
       http://www.ibm.com/developerworks/linux/linux390/october2005_documentation.html
     * Starting with z9 HiperSocket firmware returns the version
       string in a different format. This change resulted in missing
       mcl_level information in the qeth status message issued during
       online setting of the device. The updated qeth driver now
       correctly reads the new version string format of HiperSockets,
       allowing for a standardization of output format. (BZ#479881)
     * In Red Hat Enterprise Linux 5.4, the s390utils package has
       been rebased to version 1.8.1. For a full list of features
       that this rebase provides, please refer to the Package Updates
       section of the Technical Notes. (BZ#477189)
     * In the kernel, a sysfs interface has been implemented to
       associate actions to shutdown triggers. For more details on
       this feature, refer to the "Shutdown actions" chapter in IBM's
       "Device Drivers, Features, and Commands" book located at:
       http://www.ibm.com/developerworks/linux/linux390/development_documentation.html

8. Kernel Updates

  8.1. General Kernel Feature Support

     * Previously, support for raw devices in the upstream kernel was
       deprecated. However, this support has been returned to the
       kernel. Consequently, in Red Hat Enterprise Linux 5.4, support
       for raw devices has also been returned. Additionally, the
       initscripts packages have been updated, adding the previously
       dropped functionality of raw devices.(BZ#472891)
     * KVM guest-smp tlb flushing without mmu-notifiers could corrupt
       memory as a KVM may add pages to the kernel freelist while
       another vcpu may still be writing to them through guest mode.
       This update adds mmu-notifier support to the kernel and also
       corrects a bug found in an earlier patch wherein mm_struct was
       grown by existing drivers and caused a failed kABI check. This
       bug has been corrected by using an index that resides in an
       unused padding hole to avoid expanding the structure
       size.(Bugzilla #485718)
     * Pointer and signed arithmetic overflow wrapping has not
       previously been defined in the Linux kernel. This could cause
       GCC (GNU C Compiler) to assume that wrapping does not occur
       and attempt to optimize the arithmetic that the kernel may
       require for overflow testing. This update adds the -fwrapv
       variable to GCC CFLAGS in order to define wrapping
       behavior.(Bugzilla #491266)
     * An issue of contention between processes vying for the same
       memory space in high end systems was recently identified by
       TPC-C (Transaction Processing Council) benchmarking. This
       update includes fast-gup patches which use direct IO and
       provide a significant (up to 9-10%) performance improvement.
       This update has been tested thoroughly and is used in the 5.4
       kernel to improve scalability. For further information, see
       this article. (Bugzilla #474913)
     * A new tunable parameter has been added to this kernel,
       allowing system administrators to change the maximum number of
       modified pages kupdate writes to disk per iteration each time
       it runs. This new tunable /proc/sys/vm/max_writeback_pages
       defaults to 1024 or 4MB so that a maximum of 1024 pages get
       written out by each iteration of kupdate. (Bugzilla #479079).
     * A new option (CONFIG_TASK_IO_ACCOUNTING=y) has been added to
       kernel to assist in monitoring IO statistics per process. This
       assists with troubleshooting in a production environment.
       (Bugzilla #461636)
     * In previous kernels, back-up processes were deteriorating DB2
       server responsiveness. This was caused by
       /proc/sys/vm/dirty_ratio preventing processes writing to
       pagecache memory when more than half of the unmapped pagecache
       memory was dirty (even if dirty_ratio was set to 100%). A
       change made in this kernel update overrides this limiting
       behavior. Now, when the dirty_ratio is set to 100%, the system
       will no longer limit writing to pagecache memory. (Bugzilla
       #295291)
     * The rd_blocksize option found in the previous kernel's ramdisk
       driver was causing data corruption when using large ramdisks
       under a reasonable system load. This update removes the
       unnecessary option and resolves the data corruption issues.
       (Bugzilla #480663)
     * The function getrusage is used to examine the resource usage
       of a process. It is useful in diagnosing problems and
       gathering data on resource usage. In instances where a process
       interrogated by getrusage was spawning child process threads,
       however, the results would be in incorrect as getrusage would
       examine only the parent process and not interrogate its
       children. This update implements rusadge_thread to allow for
       accurate resource usage results in these instances. (Bugzilla
       #451063)
     * The header /usr/include/linux/futex.h would previously
       interfere with compiling C source code files, resulting in an
       error. This update includes a patch which corrects problematic
       kernel only definitions and resolves the compiling error.
       (Bugzilla #475790)
     * In previous kernels the kernel version was not identified in
       panic or oops output messages. This update adds the kernel
       version details to oops and panic output. (Bugzilla #484403)
     * During release 2.6.18, the kernel was configured to provide
       kernel-headers for the package glibc. That process caused
       various files to be improperly marked for inclusion. The
       serial_reg.h file was incorrectly marked and not included in
       the kernel_headers rpm. This, in turn, caused problems with
       building other rpms. This update adds the serial_reg.h file
       and corrects the problem. (Bugzilla #463538)
     * In some circumstances upcrund, the process manager in the HP
       Unified Parallel C (UPC) product, returned an ESRCH result and
       failed when calling setpgid() for a child process forked by a
       sub-thread. This update includes a patch to fix for this
       problem. (Bugzilla #472433)
     * Functionality has been added to sysrq-t to display backtrace
       information about running processes. This will assist in
       debugging hung systems. (Bugzilla #456588)

    8.1.1. Debugging

   In Red Hat Enterprise Linux 5.4, debugging the kernel has been
   improved with added features for generating core dumps. Core dumps
   (memory snapshots) are useful for debugging system and kernel
   crashes. With this update, it is now possible to perform a core
   dump on systems that utilize hugepages.(BZ#470411) Additionally,
   kernel panic messages can now be extracted from a core dump file
   (vmcore) using the makedumpfile command. (BZ#485308)

    8.1.2. Security

     * This update increases the maximum length of the kernel key
       field from the arbitrary 32 character length set in previous
       kernels to 255 characters. (Bugzilla #475145)
     * This kernel update addresses the security concern arising from
       non-root users being able to create device nodes on
       filesystems exported using NFSD (Network File System daemon).
       This update returns the CAP_MKNOD and CAP_LINUX_IMMUTABLE)
       capabilities to the user with the FSUID of 0 in the file
       system mask. (Bugzilla #497272 and Bugzilla #499076)
     * In keeping with Federal Information Processing Standardization
       140 (FIPS140) certification requirements, this update
       includes:

          * Self-testing for; ansi_cprng (Bugzilla #497891), ctr(aes)
            mode (Bugzilla #497888), Hmac-sha512 (Bugzilla #499463),
            rfc4309(ccm(aes)). (Bugzilla #472386), .
          * Code to produce a signature file that GRUB performs a
            checksum against during the boot process. (Bugzilla
            #444632)
          * Code to change the DSA key from 512 bit to 1024 bit for
            module signing. (Bugzilla #413241)

  8.2. General Platform Support

   Throttling State (T-State) notification support has been added to
   the Advanced Configuration and Power Interface (ACPI)
   implementation in the kernel. Adding T-State notification enhances
   the use of Intel® Intelligent Power Node Manager technology for
   power management in data centers.(BZ#487567).

  8.3. Driver Updates

    8.3.1. Open Fabrics Enterprise Distribution (OFED) Drivers

   The OpenFabrics Alliance Enterprise Distribution (OFED) is a
   collection of Infiniband and iWARP hardware diagnostic utilities,
   the Infiniband fabric management daemon, Infiniband/iWARP kernel
   module loader, and libraries and development packages for writing
   applications that use Remote Direct Memory Access (RDMA)
   technology. Red Hat Enterprise Linux uses the OFED software stack
   as its complete stack for Infiniband/iWARP/RDMA hardware support.
   In Red Hat Enterprise Linux 5.4, the following portions of OFED
   have been updated to the upstream version 1.4.1-rc3

     * Remote Direct Memory Access (RDMA) headers (BZ#476301)
     * Reliable Datagram Sockets (RDS) protocol (BZ#477065,
       BZ#506907)
     * Sockets Direct Protocol (SDP) (BZ#476301)
     * SCSI RDMA Protocol (SRP) (BZ#476301)
     * IP over InfiniBand (IPoIB) (BZ#434779, BZ#466086, BZ#506907)

   Additionally, the following OFED drivers have been updated to the
   upstream version 1.4.1-rc3:

     * The cxgb3 and iw_cxgb3 drivers for the Chelsio T3 Family of
       network devices (BZ#476301, BZ#504906)
     * The driver for mthca-based InfiniBand HCA (Host Channel
       Adapter) (BZ#476301, BZ#506097)
     * qlgc_vnic driver (BZ#476301)

Note

   Red Hat closely tracks the upstream OFED code base in order to
   provide a maximal level of enablement for this still evolving
   technology. As a consequence, Red Hat can only preserve API/ABI
   compatibility across minor releases to the degree that the
   upstream project does. This is an exception from the general
   practice in the development of Red Hat Enterprise Linux.

    8.3.2. General Driver Updates

     * The i5400 driver for Intel 5400 class Memory Controllers has
       been updated with added support for Error Detection And
       Correction (EDAC). (BZ#462895)
     * the i2c driver for the iic-bus interface has been updated,
       adding support for the AMD SB800 Family of products.
     * The i2c-piix4 driver has been updated with support for the
       Broadcom HT1100 chipset. (BZ#474240)
     * The hpilo driver has been updated.(BZ#488964).
     * The dm9601 for Davicom Ethernet Adaptors has been updated.

    8.3.3. Network Driver Updates

     * the bonding driver has been updated to the latest upstream
       version. This update, however has introduced symbol/ipv6
       module dependency capabilities. Therefore, if IPv6 has been
       previously disabled (by inserting the install ipv6 /bin/false
       line in the /etc/modprobe.conf file) an upgrade to the bonding
       driver in 5.4 will result in the bonding kernel module failing
       to load. The install ipv6 /bin/false line needs to be replaced
       with install ipv6 "disable=1 for the module to load properly.
     * The drivers in the kernel for Intel® I/O Acceleration
       Technology (Intel® I/OAT) have been updated to version
       2.6.24.(BZ#436048).
     * the igb driver for Intel® Gigabit Ethernet Adapters has been
       updated to version 1.3.16-k2. This update also enables GRO
       support for the igb driver. (BZ#484102, BZ#474881, BZ#499347).
     * The igbvf driver has been updated, providing Virtual Function
       support for Intel 82576 Gigabit Ethernet Controllers.
       (BZ#480524)
     * the ixgbe driver for Intel 10 Gigabit PBetaCI Express network
       devices has been updated to version 2.0.8-k2. This update also
       enables GRO support for the ixgbe driver. (BZ#472547,
       BZ#499347).
     * The bnx2 driver for Broadcom NetXtreme II network devices has
       been updated to version 1.9.3 (BZ#475567 BZ#476897 BZ#489519)
     * The tg3 driver for Broadcom Tigon3 ethernet devices has been
       updated to version 3.96. (BZ#481715, BZ#469772). This driver
       update adds support for 5785F and 50610M devices. (BZ#506205)
     * The cnic driver has been added, providing Internet Small
       Computer System Interface (iSCSI) support for bnx2 network
       devices. (BZ#441979).
     * The bnx2x driver for Broadcom Everest network devices has been
       updated to version 1.48.105.(BZ#475481).
     * The bnx2i driver has been added, providing iSCSI support for
       bnx2x network devices. (BZ#441979).
     * The cxgb3 driver for the Chelsio T3 Family of network devices
       has been updated, enabling iSCSI TCP Offload Engines (TOE) and
       Generic Receive Offload (GRO) support. (BZ#439518, BZ#499347)
     * The forcedeth ethernet driver for NVIDIA nForce devices has
       been updated to version 0.62. (BZ#479740).
     * The sky2 driver for ethernet controllers using the Marvell
       Yukon 2 chipset has been updated. (BZ#484712).
     * The enic driver for Cisco 10G ethernet devices has been
       updated to version 1.0.0.933. (BZ#484824)
     * The e1000e driver for Intel PRO/1000 ethernet devices has been
       updated to the upstream version 1.0.2-k2. (BZ#480241)
     * The be2net driver for Emulex Tiger Shark converged network
       adapters has been added as a Technology Preview.

    8.3.4. Storage Driver Updates

     * The bnx2 driver now supports iSCSI. The bnx2i driver will
       access the bnx2 driver through the cnic module to provide
       iSCSI offload support. To manage bnx2i, use the
       iscsi-initiator-utils package. For instructions on bnx2i
       configuration, please refer to section 5.1.2 of the
       /usr/share/docs/iscsi-initiator-utils-<version>/README file.
       (BZ#441979 and BZ#441979)
       Note that the bnx2i version included in this release does not
       support IPv6.
     * The md driver has been updated to provide support for bitmap
       merging. This feature eliminates the need for full resync when
       performing data replication. (BZ#481226)
     * The scsi layer in this release features the following updates:

          * The scsi driver now includes the upstream scsi_dh_alua
            module. This adds explicit asymmetric logical unit access
            (ALUA) support with this release. To utilize the
            scsi_dh_alua module when using dm-multipath, specify alua
            as the hardware_handler type in multipah.conf.
            (BZ#482737)
            Note that for EMC Clariion devices, using only
            scsi_dh_alua or dm-emc alone is supported. Using both
            scsi_dh_alua and dm-emc is not supported.
          * The rdac_dev_list structure now includes md3000 and
            md3000i entries. This allows users to benefit from the
            advantages provided by the iscsi_dh_rdac module.
            (BZ#487293)
          * A bug that caused iSCSI iBFT installations to panic
            during disk formatting is now fixed. (BZ#436791)
          * A bug in the iscsi_r2t_rsp struct that caused kernel
            panics during iSCSI failovers in some multipathed
            environments is now fixed. (BZ#484455)

     * The cxgb3 driver has been updated to apply several upstream
       fixes and provide support for iSCSI TOE devices. (BZ#439518)
       Note that the cxgb3i version included in this release does not
       support IPv6.
     * This release includes the new mpt2sas driver. This driver
       supports the SAS-2 family of adapters from LSI Logic. SAS-2
       increases the maximum data transfer rate from 3Gb/s to 6Gb/s.
       The mpt2sas driver is located in the drivers/scsi/mpt2sas
       directory, as opposed to the older mpt drivers that are
       located in drivers/message/fusion directory. (BZ#475665)
     * The aacraid driver has now been updated to version 1.1.5-2461.
       This update applies several upstream fixes for bugs affecting
       queued scans, controller boot problems, and other issues.
       (BZ#475559)
     * The aic7xxx driver now features an increased maximum I/O size.
       This allows supported devices (such as SCSI tape devices) to
       perform writes with larger buffers.
     * The cciss driver has been updated to apply upstream fixes for
       bugs affecting memory BAR discovery, the rebuild_lun_table and
       the MSA2012 scan thread. This update also applies several
       configuration changes to cciss.
     * The fnic driver has been updated to version 1.0.0.1039. This
       applies several upstream bug fixes, updates the libfc and fcoe
       modules, and adds a new module parameter that controls debug
       logging at runtime. (BZ#484438)
     * The ipr driver now supports MSI-X interrupts. (BZ#475717)
     * The lpfc driver has been updated to version 8.2.0.48. This
       enables hardware support for upcoming OEM programs. In
       addition, this update also applies the following bug fixes
       (among others):(BZ#476738 and BZ#509010)

          * Virtualized fibre-channel switches are now supported.
          * Polling for error attention interrupts are now available.
          * A bug that caused memory leaks in vport create and delete
            loop is now resolved.

       With this update, the lpfc driver now also supports HBAnyware
       4.1 and OneConnect UCNA. (BZ#498524)
     * The MPT fusion driver is now updated to version 3.04.07rh v2.
       This applies several bug fixes, including: (BZ#475455)

          * An MPT fusion driver bug that prevented the system from
            booting with the PAE kernel is now fixed.
          * Controllers are now set to READY_STATE when the driver
            unloads.
          * The mptsas driver now issues TUR (Test Unit Ready) and
            Report LUN commands before adding a device to the
            transport layer.

       In addition, a patch that unexpectedly caused mptctl_ioctl()
       to issue numerous yet benign kernel error messages is now
       reverted. With this release, mptctl_ioctl() no longer issues
       these kernel error messages.
     * The megaraid_sas driver is now updated to version 4.08-RH1.
       This update applies the following upstream enhancements and
       fixes (among others):(BZ#475574)

          * This upate adds a polling mode to the driver.
          * A bug affecting supported tape drives is now fixed. With
            this release, the pthru timeout value is now set to the
            O/S layer timeout value for commands sent to tape drives.

     * The mvsas driver is now updated to version 0.5.4. This applies
       several fixes and enhancements from upstream, and adds support
       for Marvell RAID bus controllers MV64460, MV64461, and
       MV64462. (BZ#485126)
     * The qla2xxx driver has been updated to version
       8.03.00.10.05.04-k, and now supports Fibre Channel over
       Convergence Enhanced Ethernet adapters. With this release,
       qla2xxx also applies several bug fixes from upstream,
       including: (BZ#471900, BZ#480204, BZ#495092, and BZ#495094)

          * Discrepancies detected during OVERRUN handling on 4GB and
            8GB adapters are now corrected.
          * All vports are now alerted of any asynchronous events.
          * A bug that caused kernel panics with the QLogic 2472 card
            is now fixed.
          * The stop_firmware command is no longer retried if the
            first attempt results in a times out.
          * The sector mask value is no longer based on the fixed
            optrom size.
          * A bug that caused frequent path failures during I/O on
            multipathed devices is now fixed. (BZ#244967)
          * The driver source code is now kABI-compliant.
          * dcbx pointers are now set to NULL after freeing memory.

       In addition to these updates, the qla24xx and qla25xx
       firmwares included in the qla2xxx driver are now updated to
       version 4.04.09.
     * The qla4xxx driver now features improved driver fault
       recovery. This update fixes a bug in the driver that prevented
       adapter recovery if there were outstanding commands detected
       on the host adapter. (BZ#497478)
     * This release includes the new qlge driver. This driver adds
       ethernet support for QLogic FCoE 10GB adapters. (BZ#479288)

9. Technology Previews

   Technology Preview features are currently not supported under Red
   Hat Enterprise Linux subscription services, may not be
   functionally complete, and are generally not suitable for
   production use. However, these features are included as a customer
   convenience and to provide the feature with wider exposure.
   The following Technology Previews are new or enhanced in Red Hat
   Enterprise Linux 5.4 beta. For detailed information on the
   Technology Previews in Red Hat Enterprise Linux 5.4, refer to the
   Technology Previews section of the 5.4 Technical Notes located at
   http://www.redhat.com/docs/manuals/enterprise/

     * New Emulex Tiger Shark converged network adapter driver. Refer
       to Section 8.3.3, “Network Driver Updates” for more
       information.
     * New Systemtap Tracepoints. Refer to Section 8.1.1, “Debugging”
       for more information.
     * New Gnu Compiler Collection version 4.4. Refer to Section 6,
       “Tools Updates” for more information.
     * Updated ext4 support. Refer to Section 4, “Filesystems
       Updates” for more information.
     * glibc new MALLOC behaviour. Refer to Section 6, “Tools
       Updates” for more information.
     * samba3x and ctdb on the x86_64 platform. Refer to Section 4,
       “Filesystems Updates” for more information.
     * Clustering with KVM hypervisor. Refer to Section 2,
       “Clustering Updates” for more information.
     * The fence_virsh fence agent is provided in this release of Red
       Hat Enterprise Linux as a Technology Preview. Refer to
       Section 2.1, “Fencing Improvements” for more information.
     * USB passthough with the KVM hypervisor is considered to be a
       Technology Preview for the 5.4 release.
     * In Red Hat Enterprise Linux 5.4, Logical Partition (LPAR)
       support for the cluster-suite is considered a Technology
       Preview. (BZ#480662, BZ#498083)
     * The xorg-x11-qxl-drv X11 video driver for the qemu QXL video
       accelerator has been added to 5.4 as a Technology Preview.
       (BZ#489806)

A. Revision History

   Revision History                                                  
   Revision 0.4          Thu Jul 23 2009          Don Domingo        
   Processed Storage Driver Updates section for SME tech review      
   Revision 0.3          Thu Jul 02 2009          Ryan Lerch         
   Fixed various typos, added Beta Specific Known Issues.            
   Revision 0.2          Wed Jul 01 2009          Ryan Lerch         
   Beta Release Notes.                                               
   Revision 0.1          Tue Apr 21 2009          Ryan Lerch         
   Moved relevant content over from 5.3 Release Notes.               

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   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=474881
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=499347
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=480524
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=472547
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=499347
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=475567
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=476897
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=489519
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=481715
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=469772
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=506205
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=441979
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=475481
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=441979
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=439518
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=499347
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=479740
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=484712
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=484824
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=480241
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=441979
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=441979
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=481226
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=482737
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=487293
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=436791
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=484455
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=439518
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=475665
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=475559
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=484438
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=475717
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=476738
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=509010
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=498524
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=475455
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=475574
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=485126
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=471900
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=480204
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=495092
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=495094
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=244967
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=497478
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=479288
   . http://www.redhat.com/docs/manuals/enterprise/
   . 8.3.3. Network Driver Updates
	file:///home/rlerch/source/SVN/Red_Hat_Enterprise_Linux/5.4/Release_Notes/tmp/en-US/html-single/index.html#NetworkDrivers
   . 8.1.1. Debugging
	file:///home/rlerch/source/SVN/Red_Hat_Enterprise_Linux/5.4/Release_Notes/tmp/en-US/html-single/index.html#Debugging
   . 6. Tools Updates
	file:///home/rlerch/source/SVN/Red_Hat_Enterprise_Linux/5.4/Release_Notes/tmp/en-US/html-single/index.html#Tools
   . 4. Filesystems Updates
	file:///home/rlerch/source/SVN/Red_Hat_Enterprise_Linux/5.4/Release_Notes/tmp/en-US/html-single/index.html#Filesystems
   . 6. Tools Updates
	file:///home/rlerch/source/SVN/Red_Hat_Enterprise_Linux/5.4/Release_Notes/tmp/en-US/html-single/index.html#Tools
   . 4. Filesystems Updates
	file:///home/rlerch/source/SVN/Red_Hat_Enterprise_Linux/5.4/Release_Notes/tmp/en-US/html-single/index.html#Filesystems
   . 2. Clustering Updates
	file:///home/rlerch/source/SVN/Red_Hat_Enterprise_Linux/5.4/Release_Notes/tmp/en-US/html-single/index.html#Clustering
   . 2.1. Fencing Improvements
	file:///home/rlerch/source/SVN/Red_Hat_Enterprise_Linux/5.4/Release_Notes/tmp/en-US/html-single/index.html#Fencing
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=480662
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=498083
   . https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=489806