Release Notes Updates

Installation-Related Notes

Feature Updates

Driver Updates

Kernel-Related Updates

Other Updates

Technology Previews

Resolved Issues

Known Issues

When installing Red Hat Enterprise Linux 5 on a fully virtualized SMP guest, the installation may freeze. This can occur when the host (dom0) is running Red Hat Enterprise Linux 5.1.

To prevent this, set the guest to use a single processor using the install. You can do this by using the --vcpus=1 option in virt-install. Once the installation is completed, you can set the guest to SMP by modifying the allocated vcpus in virt-manager.

This release includes WBEMSMT, a suite of web-based applications that provides a user-friendly management interface for Samba and DNS. For more information about WBEMSMT, refer to http://sblim.wiki.sourceforge.net/.

Upgrading pm-utils from a Red Hat Enterprise Linux 5.1 Beta version of pm-utils will fail, resulting in the following error:

error: unpacking of archive failed on file /etc/pm/sleep.d: cpio: rename

To prevent this from occurring, delete the /etc/pm/sleep.d/ directory prior to upgrading. If /etc/pm/sleep.d contains any files, you can move those files to /etc/pm/hooks/.

Hardware testing for the Mellanox MT25204 has revealed that an internal error occurs under certain high-load conditions. When the ib_mthca driver reports a catastrophic error on this hardware, it is usually related to an insufficient completion queue depth relative to the number of outstanding work requests generated by the user application.

Although the driver will reset the hardware and recover from such an event, all existing connections are lost at the time of the error. This generally results in a segmentation fault in the user application. Further, if opensm is running at the time the error occurs, then it will have to be manually restarted in order to resume proper operation.

Driver Update Disks now support Red Hat's Driver Update Program RPM-based packaging. If a driver disk uses the newer format, it is possible to include RPM packaged drivers that will be preserved across system updates.

Please note that driver RPMs are copied only for the default kernel variant that is in use on the installed system. For example, installing a driver RPM on a system running the virtualized kernel will install the driver only for the virtualized kernel. The driver RPM will not be installed for any other installed kernel variant in the system.

As such, on a system that has multiple kernel variants installed, you will need to boot the system on each kernel variant and install the driver RPM. For example, if your system has both bare-metal and virtualized kernels installed, boot your system using the bare-metal kernel and install the driver RPM. Then, reboot the system into the virtualized kernel and install the driver RPM again.

During the lifetime of dom0, you cannot create guests (i.e. xm create) more than 32,750 times. For example, if you have guests rebooting in a loop, dom0 will fail to boot any guest after rebooting guests a total of 32,750 times.

If this event occurs, restart dom0

The Red Hat Enterprise Linux 5.1 NFS server now supports referral exports. These exports are based on extensions to the NFSv4 protocol. Any NFS clients that do not support these extensions (namely, Red Hat Enterprise Linux releases prior to 5.1) will not be able to access these exports.

As such, if an NFS client does not support these exports, any attempt to access these exports may fail with an I/O error. In some cases, depending on the client implementation, the failure may be more severe, including the possibility of a system crash.

It is important that you take precautions to ensure that NFS referral exports are not accessed by clients that do not support them.

GFS2 is an incremental advancement of GFS. This update applies several significant improvements that require a change to the on-disk file system format. GFS file systems can be converted to GFS2 using the utility gfs2_convert, which updates the metadata of a GFS file system accordingly.

While much improved since its introduction in Red Hat Enterprise Linux 5, GFS2 remains a Technology Preview. The release notes included in the distribution incorrectly states that GFS2 is fully supported. Nevertheless, benchmark tests indicate faster performance on the following:

In addition, GFS2 also features the following changes:

Installing Red Hat Enterprise Linux 5.1 on HP BL860c blade systems may hang during the IP information request stage. This issue manifests when you have to select OK twice on the Configure TCP/IP screen.

If this occurs, reboot and perform the installation with Ethernet autonegotiation disabled. To do this, use the parameter ethtool="autoneg=off" when booting from the installation media. Doing so does not affect the final installed system.

The nohide export option is required on referral exports (i.e. exports that specify a referral server). This is because referral exports need to "cross over" a bound mount point. The nohide export option is required for such a "cross over" to be successful.

For more information on bound mounts, refer to man exports 5.

This update includes the lvm2 event monitoring daemon. If you are already using lvm2 mirroring, perform the following steps to ensure that all monitoring functions are upgraded properly:

Rapid Virtualization Indexing (RVI) is now supported on 64-bit, 32-bit, and 32-bit PAE kernels. However, RVI can only translate 32-bit guest virtual addresses on the 32-bit PAE hypervisor.

As such, if a guest is running a PAE kernel with more than 3840MB of RAM, a wrong address translation error will occur. This can crash the guest.

It is recommended that you use the 64-bit kernel if you intend to run guests with more than 4GB of physical RAM under RVI.

Running 16 cores or more using AMD Rev F processors may result in system resets when performing fully-virtualized guest installations.

Installing the systemtap-runtime package will result in a transaction check error if the systemtap package is already installed. Further, upgrading Red Hat Enterprise Linux 5 to 5.1 will also fail if the systemtap package is already installed.

As such, remove the systemtap package using the command rpm -e systemtap-0.5.12-1.e15 before installing systemtap-runtime or performing an upgrade.

When setting up NFSROOT, BOOTPROTO must be set as BOOTPROTO=dhcp in /etc/sysconfig/network-scripts/ifcfg-eth0.

If your environment requires a different setting for BOOTPROTO, then temporarily set BOOTPROTO=dhcp in /etc/sysconfig/network-scripts/ifcfg-eth0 before initially creating the initrd. You can reset the original value of BOOTPROTO after the initrd is created.

The QLogic iSCSI Expansion Card for the IBM Bladecenter provides both ethernet and iSCSI functions. Some parts on the card are shared by both functions. However, the current qla3xxx and qla4xxx drivers support ethernet and iSCSI functions individually. Both drivers do not support the use of ethernet and iSCSI functions simultaneously.

As such, using both ethernet and iSCSI functions simultaneously may hang the device. This could result in data loss and filesystem corruption on iSCSI devices, or network disruptions on other connected ethernet devices.

When using virt-manager to add disks to an existing guest, duplicate entries may be created in the guest's /etc/xen/<domain name> configuration file. These duplicate entries will prevent the guest from booting.

As such, you should remove these duplicate entries.

Repeatedly migrating a guest between two hosts may cause one host to panic. If a host is rebooted after migrating a guest out of the system and before migrating the same guest back, the panic will not occur.

sysreport is being deprecated in favor of sos. To install sos, run yum install sos. This command installs sos and removes sysreport. It is recommended that you update any existing kickstart files to reflect this.

After installing sos, use the command sosreport to invoke it. Using the command sysreport generates a warning that sysreport is now deprecated; continuing will invoke sosreport.

If you need to use the sysreport tool specifically, use the command sysreport.legacy to invoke it.

For more information about sosreport, refer to man sosreport and sosreport --help.

If you are copying the contents of the Red Hat Enterprise Linux 5 CD-ROMs (in preparation for a network-based installation, for example) be sure to copy the CD-ROMs for the operating system only. Do not copy the Supplementary CD-ROM, or any of the layered product CD-ROMs, as this will overwrite files necessary for Anaconda's proper operation.

The contents of the Supplementary CD-ROM and other layered product CD-ROMs must be installed after Red Hat Enterprise Linux 5.1 has been installed.

When installing Red Hat Enterprise Linux 5.1 on a fully virtualized guest, do not use the kernel-xen kernel. Using this kernel on fully virtualized guests can cause your system to hang.

If you are using an Installation Number when installing Red Hat Enterprise Linux 5.1 on a fully virtualized guest, be sure to deselect the Virtualization package group during the installation. The Virtualization package group option installs the kernel-xen kernel.

Note that paravirtualized guests are not affected by this issue. Paravirtualized guests always use the kernel-xen kernel.

If you are using the Virtualized kernel when upgrading from Red Hat Enterprise Linux 5 to 5.1, you must reboot after completing the upgrade. You should then boot the system using the updated Virtualized kernel.

The hypervisors of Red Hat Enterprise Linux 5 and 5.1 are not ABI-compatible. If you do not boot the system after upgrading using the updated Virtualized kernel, the upgraded Virtualization RPMs will not match the running kernel.

The CIFS client has been updated to version 1.48aRH. This is based upon the 1.48a release, with patches that apply the following changes:

Note that for users of the EMC Celerra product (NAS Code 5.5.26.x and below), the CIFS client hangs when accessing shares on EMC NAS. This issue is characterized by the following kernel messages:

kernel:  CIFS VFS: server not responding
kernel:  CIFS VFS: No response for cmd 162 mid 380
kernel:  CIFS VFS: RFC1001 size 135 bigger than SMB for Mid=384

After a CIFS mount, it becomes impossible to read/write any file on it and any application that attempts an I/O on the mountpoint will hang. To resolve this issue, upgrade to NAS Code 5.5.27.5 or later (use EMC Primus case number emc165978).

MODULE_FIRMWARE tags are now supported.

ICH9 controllers are now supported.

Greyhound processors are now supported in CPUID calls.

Oprofile now supports new Greyhound performance counter events.

Directed DIAG is now supported to improve z/VM utilization.

The Intel graphics chipset is now supported through the DRM kernel module. Further, the DRM API has been upgraded to version 1.3 to support direct rendering.

Updates to ACPI power management have improved S3 suspend-to-RAM and S4 hibernate.

gaim is now called pidgin.

Intel microcode updated to version 1.17. This adds support for new Intel processors.

Implicit active-active failover using dm-multipath on EMC Clariion storage is now supported.

The Chinese font Zysong is no longer installed as part of the fonts-chinese package. Zysong is now packaged separately as fonts-chinese-zysong. The fonts-chinese-zysong package is located in the Supplementary CD.

Note that the fonts-chinese-zysong package is needed to support the Chinese National Standard GB18030.

The Challenge Handshake Authentication Protocol (CHAP) username and password have a character limit of 256 each.

pump is deprecated in this update. As such, configuring your network interface through netconfig may result in broken ifcfg scripts.

To properly configure your network interface, use system-config-network instead. Installing the updated system-config-network package removes netconfig.

rpm --aid is no longer supported. It is recommended that you use yum when updating and installing packages.

A SATA bug that caused SATA-equipped systems to pause during the boot process and display an error before resuming is now fixed.

In multi-boot systems, parted now preserves the starting sector of the first primary partition where Windows Vista™ is installed. As such, when setting up a multi-boot system with both Red Hat Enterprise Linux 5.1 and Windows Vista™, the latter is no longer rendered unbootable.

rmmod xennet no longer causes domU to crash.

4-socket AMD Sun Blade X8400 Server Module systems that do not have memory configured in node 0 no longer panic during boot.

conga and luci can now be used to create and configure failover domains.

When installing the Cluster Storage group through yum, the transaction no longer fails.

During installation, incorrect SELinux contexts are no longer assigned to /var/log/faillog and /var/log/tallylog.

On the dual-core AMD Platform, cpu-intensive activity on a single cpu no longer causes CPU cores to change frequencies.

Installing Red Hat Enterprise Linux 5.1 using split installation media (for example, CD or NFSISO) no longer causes an error in the installation of amanda-server.

During the installation process, Anaconda can now detect more than 4GB of RAM. This allows Anaconda to automatically determine whether it needs to install the kernel-PAE variant of the kernel or not.

EDAC now reports the correct amount of memory on the latest k8 processors.

Logging in remotely to a Gnome desktop via gdm no longer causes the login screen to hang.

A bug in autofs that prevented multi-mounts from working properly is now fixed.

Several patches to utrace apply the following fixes:

A RealTime Clock (RTC) bug that prevented alarms and periodic RTC interrupts from working properly is now fixed.

The first time the Release Notes button is clicked in Anaconda, a delay occurs while the window renders the Release Notes. During this delay, a seemingly empty list appears in the window. The rendering normally completes quickly, so most users may not notice this.

This delay is mostly due to the fact that the package installation phase is the most CPU-intensive phase of installation.

Host bus adapters that use the MegaRAID driver must be set to operate in "Mass Storage" emulation mode, not in "I2O" emulation mode. To do this, perform the following steps:

If the adapter is incorrectly set to "I2O" emulation, the system will attempt to load the i2o driver. This will fail, and prevent the proper driver from being loaded.

Previous Red Hat Enterprise Linux releases generally do not attempt to load the I2O driver before the MegaRAID driver. Regardless of this, the hardware should always be set to "Mass Storage" emulation mode when used with Linux.

Laptops equipped with the Cisco Aironet MPI-350 wireless may hang trying to get a DHCP address during any network-based installation using the wired ethernet port.

To work around this, use local media for your installation. Alternatively, you can disable the wireless card in the laptop BIOS prior to installation (you can re-enable the wireless card after completing the installation).

Currently, system-config-kickstart does not support package selection and deselection. When using system-config-kickstart, the Package Selection option indicates that it is disabled. This is because system-config-kickstart uses yum to gather group information, but is unable to configure yum to connect to Red Hat Network.

At present, you need to update package sections in your kickstart files manually. When using system-config-kickstart to open a kickstart file, it will preserve all package information in it and write it back out when you save.

Boot-time logging to /var/log/boot.log is not available in this update of Red Hat Enterprise Linux 5. An equivalent functionality will be added in a future update.

When upgrading from Red Hat Enterprise Linux 4 to Red Hat Enterprise Linux 5, the Deployment Guide is not automatically installed. You need to use pirut to manually install it after completing the upgrade.

The system may not successfully reboot into a kexec/kdump kernel if X is running and using a driver other than vesa. This problem only exists with ATI Rage XL graphics chipsets.

If X is running on a system equipped with ATI Rage XL, ensure that it is using the vesa driver in order to successfully reboot into a kexec/kdump kernel.

When using Red Hat Enterprise Linux 5 on a machine with an nVidia CK804 chipset installed, the following kernel messages may appear:

kernel: assign_interrupt_mode Found MSI capability
kernel: pcie_portdrv_probe->Dev[005d:10de] has invalid IRQ. Check vendor BIOS

These messages indicate that certain PCI-E ports are not requesting IRQs. Further, these messages do not, in any way, affect the operation of the machine.

Removable storage devices (such as CDs and DVDs) do not automatically mount when you are logged in as root. As such, you will need to manually mount the device through the graphical file manager.

Alternatively, you can run the following command to mount a device to /media:

mount /dev/<device name> /media

The IBM System z does not provide a traditional Unix-style physical console. As such, Red Hat Enterprise Linux 5 for the IBM System z does not support the firstboot functionality during initial program load.

To properly initialize setup for Red Hat Enterprise Linux 5 on the IBM System z, run the following commands after installation:

When upgrading from Red Hat Enterprise Linux 5 to Red Hat Enterprise Linux 5.1 via Red Hat Network, yum may not prompt you to import the redhat-beta key. As such, it is advised that you import the redhat-beta key manually prior to upgrading. To do this, run the following command:

rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-beta

When a LUN is deleted on a configured filer, the change is not reflected on the host. In such cases, lvm commands will hang indefinitely when dm-multipath is used, as the LUN has now become stale.

To work around this, delete all device and mpath link entries in /etc/lvm/.cache specific to the stale LUN.

To find out what these entries are, run the following command:

ls -l /dev/mpath | grep <stale LUN>

For example, if <stale LUN> is 3600d0230003414f30000203a7bc41a00, the following results may appear:

lrwxrwxrwx 1 root root 7 Aug  2 10:33 /3600d0230003414f30000203a7bc41a00 -> ../dm-4
lrwxrwxrwx 1 root root 7 Aug  2 10:33 /3600d0230003414f30000203a7bc41a00p1 -> ../dm-5

This means that 3600d0230003414f30000203a7bc41a00 is mapped to two mpath links: dm-4 and dm-5.

As such, the following lines should be deleted from /etc/lvm/.cache:

/dev/dm-4 
/dev/dm-5 
/dev/mapper/3600d0230003414f30000203a7bc41a00
/dev/mapper/3600d0230003414f30000203a7bc41a00p1
/dev/mpath/3600d0230003414f30000203a7bc41a00
/dev/mpath/3600d0230003414f30000203a7bc41a00p1

When attempting to create a fully virtualized Windows™ guest from a CD or DVD, the second stage of the guest install might not continue upon reboot.

To work around this, edit /etc/xen/<name of guest machine> by properly appending an entry for the CD / DVD device.

If an installation to a simple file is used as a virtual device, the disk line of /etc/xen/<name of guest machine> will read like the following:

disk = [ 'file:/PATH-OF-SIMPLE-FILE,hda,w']

A DVD-ROM device located on the host as /dev/dvd can be made available to stage 2 of the installation as hdc by appending an entry like 'phy:/dev/dvd,hdc:cdrom,r'. As such, the disk line should now read as follows:

disk = [ 'file:/opt/win2003-sp1-20061107,hda,w', 'phy:/dev/dvd,hdc:cdrom,r']

The precise device path to use may vary depending on your hardware.

If the sctp module is not added to the kernel, running netstat with the -A inet or -A inet6 option abnormally terminates with the following message:

netstat: no support for `AF INET (sctp)' on this system.	

To avoid this, install the sctp kernel module.

Current kernels do not assert Data Terminal Ready (DTR) signals before printing to serial ports during boot time. DTR assertion is required by some devices; as a result, kernel boot messages are not printed to serial consoles on such devices.

The AMD 8132 and HP BroadCom HT100 used on some platforms (such as the HP dc7700) do not support MMCONFIG cycles. If your system uses either chipset, your PCI configuration should use the legacy PortIO CF8/CFC mechanism. To configure this, boot the system with the kernel parameter -pci nommconfig during installation and add pci=nommconf to GRUB after rebooting.

Further, the AMD 8132 chipset does not support Message Signaled Interrupts (MSI). If your system uses this chipset, you should also disable MSI. To do this, use the kernel parameter -pci nomsi during installation and add pci=nomsi to GRUB after rebooting.

However, if your specific platform is already blacklisted by the kernel, your system does not require the aforementioned pci kernel parameters. The following HP platforms are already blacklisted by the kernel:

When running the bare-metal (non-Virtualized) kernel, the X server may not be able to retrieve EDID information from the monitor. When this occurs, the graphics driver will be unable to display resolutions highers than 800x600.

To work around this, add the following line to the ServerLayout section of /etc/X11/xorg.conf:

Option "Int10Backend" "x86emu"

The Virtual Machine Manager (virt-manager) included in this release does not allow users to specify additional boot arguments to the paravirtualized guest installer. This is true even when such arguments are required to install certain types of paravirtualized guests on specific types of hardware.

This issue will be addressed in a future release of virt-manager. To specify arbitrary kernel arguments in installing paravirtualized guests from the command line, use virt-install.

With the default dm-multipath configuration, Netapp devices may take several minutes to complete failback after a previously failed path is restored. To resolve this problem, add the following Netapp device configuration to the devices section of the multipath.conf file:

devices {
        device {
                vendor                  "NETAPP"
                product                 "LUN"
                getuid_callout          "/sbin/scsi_id -g -u -s /block/%n"
                prio_callout            "/sbin/mpath_prio_netapp /dev/%n"
                features                "1 queue_if_no_path"
                hardware_handler        "0"
                path_grouping_policy    group_by_prio
                failback                immediate
                rr_weight               uniform
                rr_min_io               128
                path_checker            directio
        }