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## Introduction

Red Hat Enterprise Linux minor releases are an aggregation of individual enhancement, security and bug fix errata. The Red Hat Enterprise Linux 4.9 Release Notes documents the major changes made to the Red Hat Enterprise Linux 4 operating system and its accompanying applications for this minor release.

Detailed information on the changes that each updated package provides is available in the Errata Documentation for each package.

Red Hat Enterprise Linux 4 Lifecycle. Red Hat is releasing the 9th minor release update for Red Hat Enterprise Linux 4. This update transitions Red Hat Enterprise Linux to the Production III life cycle phase. This update is being released as an online only update on Red Hat Network. No new media kits are being issued. Red Hat Enterprise Linux 4 is now closed for new feature requests and new hardware enablement. Red Hat will continue to deliver security and bug fixes for Red Hat Enterprise Linux 4 until the End-of-Life scheduled for February 29, 2012. Customers requiring longer life cycle support should contact Red Hat or its support partners for Extended Life Cycle phase support programs.

## Installation

Installation of Red Hat Enterprise Linux 4.9 is completed by upgrading from Red Hat Enterprise Linux 4.8. To update a Red Hat Enterprise Linux 4.8 installation, first ensure that the system is subscribed to the 4.9 channel, then use the up2date command:

    up2date --update

### Important

Before upgrading, ensure that the system has the most recent version of the up2date tool installed by running the command up2date up2date

There is no media kit available for Red Hat Enterprise Linux 4.9.

## Driver Updates

The `kernel-utils` package provides `microcode_ctl` utility code and the microcode data itself — supplied by Intel — to assist the kernel in updating the CPU microcode at system boot time. This microcode supports all current Intel x86- and Intel 64-based CPU models and takes advantage of the mechanism built-in to Linux that allows microcode to be updated after system boot. When loaded, the updated microcode corrects the behavior of various Intel processors, as described in processor specification updates issued by Intel for those processors. In the Red Hat Enterprise Linux 4.9 release the kernel-utils package has been updated with the 2010-09-14 version of Intel's microcode.

## General Updates

Intel Xeon support in OProfile. OProfile is a system-wide Linux profiler, capable of running at low overhead. It consists of a kernel driver and a daemon for collecting raw sample data, along with a suite of tools for parsing that data into meaningful information. OProfile is generally used by developers to determine which sections of code consume the most amount of CPU time, and why.

OProfile in Red Hat Enterprise Linux 4.9 now supports Intel Xeon (formerly codenamed Nehalem) processor performance events.

Improved Checksum support in coreutils. Newer Red Hat disk images use the SHA-256 algorithm as the checksum method. Previously, verifying these checksums on Red Hat Enterprise Linux 4 was not a simple process. Red Hat Enterprise Linux 4.9 provides and updated `coreutils` updated package, containing checksum utilities for the whole SHA-2 family, allowing a user to easily count or verify SHA-224, SHA-256, SHA-384, and SHA-512 checksums.

KornShell. KSH-93 is the most recent version of the KornShell (`ksh`) by David Korn of AT&T Bell Laboratories, a shell programming language upwards-compatible with `sh` (the Bourne Shell). In Red Hat Enterprise Linux 4.9, `ksh` is updated to the upstream release version `ksh93t+`.

Firefox. Red Hat Enterprise Linux 4.9 features version 3.6.4 of the Mozilla Firefox open source web browser. Refer to the Firefox 3.6 Release Notes and Firefox 3.6.4 Release Notes for further details on the bug fixes and enhancements provided by this update.

SystemTap. SystemTap is a tracing and probing tool that allows users to study and monitor the activities of the operating system (particularly, the kernel) in fine detail. It provides information similar to the output of tools like netstat, ps, top, and iostat; however, SystemTap is designed to provide more filtering and analysis options for collected information.

SystemTap in Red Hat Enterprise Linux 4.9 has been updated to version 1.3. Most notably, this update provides support for the newer kprobe capabilities.

## Technology Previews

Technology Preview features are currently not supported under Red Hat Enterprise Linux 4.9 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.

Customers may find these features useful in a non-production environment. Customers are also free to provide feedback and functionality suggestions for a technology preview feature before it becomes fully supported. Erratas will be provided for high-severity security issues.

During the development of a technology preview feature, additional components may become available to the public for testing. It is the intention of Red Hat to fully support technology preview features in a future release.

For more information on the scope of Technology Previews in Red Hat Enterprise Linux, please view the Technology Preview Features Support Scope page on the Red Hat website.

OpenOffice 2.0. OpenOffice 2.0 is now included in this release as a Technology Preview. This suite features several improvements, including ODF and PDF functionalities, support for digital signatures and greater compatibility with open suites in terms of format and interface. In addition to this, the OpenOffice 2.0 spreadsheet has enhanced pivot table support, and can now handle up to 65,000 rows.

For more information about OpenOffice 2.0, please refer to http://www.openoffice.org/dev_docs/features/2.0/index.html .

## Known Issues

Bugzilla #523255

  When dm-multipath is used on a storage device that implements ALUA, and `group-by-prio` is enabled, then the path groups are established when the device is configured. The paths with the same priority are grouped together, the group priority is calculated as the sum of the path priorities, and the path group with the highest sum is selected for I/O. If a path's priority changes, the group priority is re-calculated, and the active path group may change. The path grouping is not changed, even though some members of the group may now have different priorities. If you wish to re-establish the path grouping after a change, then you must enter the command

      multipathd -k"reconfigure"

Bugzilla #653424

  When dm-multipath is used on a storage device that implements ALUA, and `group-by-prio` is enabled, then the path groups are established when the device is configured. The paths with the same priority are grouped together, the group priority is calculated as the sum of the path priorities, and the path group with the highest sum is selected for I/O. If a path's priority changes, the group priority is re-calculated, and the active path group may change. The path grouping is not changed, even though some members of the group may now have different priorities. If you wish to re-establish the path grouping after a change, then you must enter the command

      multipathd -k"reconfigure"

Bugzilla #653424

  Broken dependencies in the up2date-4.8.1-33.el4_8.9 package may result in an update of the up2date package failing. Consequently, if the up2date-4.8.1-33.el4_8.9, package is installed on a system the new up2date package must be manually downloaded from the Red Hat Network and installed using the rpm command.

Bugzilla #459785

  Japanese language JP106 keyboards will not function correctly when booting into Rescue Mode on Red Hat Enterprise Linux 4.9.

Bugzilla #494022

  Updating all packages from Red Hat Enterprise Linux 4.8 to Red Hat Enterprise Linux 4.9 on multilib architectures may fail with dependency issues for the `openmpi-libs` package. To work around this issue, use the following commands to update the `compat-dapl` package before updating the remaining packages:

      up2date compat-dapl
      up2date -fu

Bugzilla #443137

  Some x86 64-bit systems may hang during boot when the `noapic` debug kernel parameter is used.

Known Issue: Bugzilla #499457

  As a result of N_Port ID Virtualization (NPIV) support added in Red Hat Enterprise Linux 4.8 on s390x architectures, the permanent_port_name sysfs attribute is no longer included. This attribute was used (primarily for debugging purposes) to differentiate the use of NPIV Logical Unit Numbers (LUNs) from within Linux. In the absence of this attribute, system administrators should refer to the Hardware Management Console / Support Element (HMC/SE) to find the virtual port address on an NPIV-enabled system.

Bugzilla #484117

  The Logical Volume Manager in Red Hat Enterprise Linux 4.9 reports file descriptor leaks, resulting in the following error returned to the installation output:

      				File descriptor NUM (socket:XXXX) leaked on lvm invocation.

  This message can be safely ignored.

Bugzilla #468097

  When installing Red Hat Enterprise Linux 4 through an Network File System (NFS) server, the installer is unable to correctly close the NFS mount points. This might cause the NFS server to misbehave. In these cases Red Hat suggests the use of an HTTP server for installations.

Bugzilla #468097

  On systems where the BIOS is able to do both legacy (`acpiphp`) and native (`pciehp`) PCI hotplugging, it is necessary for the administrator to choose a preferred method and explicitly prevent Red Hat Enterprise Linux 4 from loading the module for the undesired method. This is done by blacklisting the undesired module in `/etc/modprobe.conf`.

Bugzilla #449648

  Red Hat discourages the use of quota on EXT3 file systems. This is because in some cases, doing so can cause a deadlock.

  Testing has revealed that kjournald can sometimes block some EXT3-specific callouts that are used when quota is running. As such, Red Hat does not plan to fix this issue in Red Hat Enterprise Linux 4, as the modifications required would be too invasive.

  Note that this issue is not present in Red Hat Enterprise Linux 5.

Bugzilla #452578

  The Desktop Sharing connection icon displays its context menu when you double-click it, not when you right-click it. All other icons display their context menus when you right-click on them.

Bugzilla #451873

  If the `ib_ehca` InfiniBand driver is loaded in port auto-detection mode (using module parameter nr_ports=-1), the IP-over-InfiniBand network interfaces (ibX) might become available too late. When this occurs, the ifup ibX command issued from the openibd startup script will fail; consequently, the ibX interface will not become available.

  When this occurs, use the command rcnetwork restart to fix the problem.

Bugzilla #451873

  In the IBM Redbook "Implementing InfiniBand in IBM System p (SG247351) manual, Table 6-3 (on page 220 of the PDF version) describes debug code bit definitions, where several HCA error indicator bits are also described.

  Note that with eHCA2 adapters, bits 46 and 47 of these error indicator bits might return false positives.

Bugzilla #366961

  On HP ICH10 workstations, audio is only enabled through the front 3.5mm jacks. As such, to receive any audio output or use recording, you should plug in your headphones, speakers, or microphones to the front jacks. At present, the rear jacks, internal speaker, and master volume for this workstation do not work.

Bugzilla #429727

  With this update, the default PCI detection and ordering mode for the following models have changed:

  - HP Proliant DL 580 G5

  - HP Proliant DL 385 G2

  - HP Proliant DL 585 G2

  These models use a device scanning and enumeration mode which is not the default for Red Hat Enterprise Linux 4 or 5. The mode used by these HP Proliant models could result in add-on cards being detected and added prior to onboard/internal devices. This unexpected ordering could cause difficulties when installing new instances of Red Hat Enterprise Linux, adding hardware, and maintenance.

  The numbering of network interface cards (NIC) for the aforementioned HP Proliant models may change when they are updated with the Red Hat Enterprise Linux 4.7 kernel. The installer changes NIC numbering if the HWADDR=MAC ADDRESS parameter is not defined in `/etc/sysconfig/network-scripts/ifcfg-eth`[X]`` for each installed NICs. As such, Red Hat recommends that you ensure this parameter is defined in order to avoid any problems arising from an unexpected NIC enumeration.

  In addition, to avoid any NIC enumeration changes after updating these HP Proliant models to Red Hat Enterprise Linux 4.7, add the kernel boot parameter pci=nobfsort to `/boot/grub/grub.conf`.

Bugzilla #232499

  When a volume group contains a mirror or snapshot, issuing the lvchange command with a volume group parameter may result in the following error messages:

      Unable to change mirror log LV fail_secondary_mlog directly
      Unable to change mirror image LV fail_secondary_mimage_0 directly
      Unable to change mirror image LV fail_secondary_mimage_1 directly

  These messages can be safely ignored.

Bugzilla #441870

  Dell PowerEdge SC1435s systems may hang during boot-up. To avoid this, edit the terminal line in `grub.conf` and replace the string serial console with console serial.

Bugzilla #456533

  The updated `ixgbe` driver does not support the Intel 82598AT (Copper Pond 10GbE).

Bugzilla #454872

  Red Hat Enterprise Linux 4.9 can detect online growing or shrinking of an underlying block device. However, there is no method to automatically detect that a device has changed size, so manual steps are required to recognize this and resize any file systems which reside on the given device(s). When a resized block device is detected, a message like the following will appear in the system logs:

      VFS: busy inodes on changed media or resized disk sdi

  If the block device was grown, then this message can be safely ignored. However, if the block device was shrunk without shrinking any data set on the block device first, the data residing on the device may be corrupted.

  It is only possible to do an online resize of a filesystem that was created on the entire LUN (or block device). If there is a partition table on the block device, then the file system will have to be unmounted to update the partition table.

Bugzilla #479467

  There is a known memory leak with the res_n* family of resolver routines (i.e. res_nquery, res_nsearch and res_nmkquery). Programs that use these functions will leak memory over time. It has been fixed in newer versions of glibc, however, the fix is too invasive to be applied to Red Hat Enterprise Linux 4. Programs that use these functions may need to be restarted occasionally to free memory.

Bugzilla #452513

  The number of devices that can be handled during installation of Red Hat Enterprise Linux 4 depends on the size of the installation initrd image. Therefore, in situations where there are many devices attached to a machine (such as heavily populated Fibre Channel setups) installation will not be possible unless number of visible devices is reduced.

Bugzilla #492371

  During installation anaconda may not remove all the Logical Volume Manager (LVM) metadata that exists on a system prior to installation. This extra metadata may cause LVM tools to report missing volume groups or logical volumes after installation. To work around this issue, remove the stale LVM metadata after the installation is complete.

Bugzilla #481190

  multipath does not silence the error messages printed by any of it's callout programs. Therefore, if multipath is run when paths are down, various error messages may be displayed. The messages that are displayed depend on the specific callout programs that multipath is using. For example, if multipath is run while there are failed scsi devices, scsi_id will print

      lt;H>:<B>:<T>:<L>:Unable to get INQUIRY vpd 1 page 0x0.
      lt;H>:<B>:<T>:<L>:sg_io failed status 0x0 0x1 0x0 0x0

  Or, if multipath -ll is run while an EMC CLARiiON is down, the mpath_prio_emc priority callout will print query command indicates error

Bugzilla #453033