A bug in the updated /etc/udev/rules.d/50-udev.rules file prevents the creation of persistent names for tape devices with numbers higher than 9 in their names. For example, a persistent name will not be created for a tape device with a name of nst12.

To work around this, add an asterisk (*) after each occurrence of the string nst[0-9] in /etc/udev/rules.d/50-udev.rules.

The smartctl tool cannot properly read SMART parameters from SATA devices.

A bug in previous versions of openmpi and lam may prevent you from upgrading these packages. This bug manifests in the following error (when attempting to upgrade openmpi or lam:

error: %preun(openmpi-[version]) scriptlet failed, exit status 2

As such, you need to manually remove older versions of openmpi and lam in order to install their latest versions. To do so, use the following rpm command:

rpm -qa | grep '^openmpi-\|^lam-' | xargs rpm -e --noscripts --allmatches

Some controller names (specifically, newer ones) printed by the cciss driver are incorrect, and will not match correctly with the names listed in the HP documentation. The cciss firmware, however, will be able to correctly print the names of each attached controller at boot-time.

When using dm-multipath, if features "1 queue_if_no_path" is specified in /etc/multipath.conf then any process that issues I/O will hang until one or more paths are restored.

To avoid this, set no_path_retry [N] in /etc/multipath.conf (where [N] is the number of times the system should retry a path). When you do, remove the features "1 queue_if_no_path" option from /etc/multipath.conf as well.

Enabling multiple installed versions of the same kernel module is not supported. In addition to this, a bug in the way kernel module versions are parsed can sometimes result in enabling an older version of the same kernel module.

Red Hat recommends that when you install a newer version of an installed kernel module, you should delete the older one first.

Executing kdump on an IBM Bladecenter QS21 or QS22 configured with NFS root will fail. To avoid this, specify an NFS dump target in /etc/kdump.conf.

IBM T60 laptops will power off completely when suspended and plugged into a docking station. To avoid this, boot the system with the argument acpi_sleep=s3_bios.

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.

Because of this limitation, successive resets (via consecutive ifdown/ifup commands) may hang the device. To avoid this, allow a 10-second interval after an ifup before issuing an ifdown. Also, allow the same 10-second interval after an ifdown before issuing an ifup. This interval allows ample time to stabilize and re-initialize all functions when an ifup is issued.

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).

Boot-time logging to /var/log/boot.log is not available in Red Hat Enterprise Linux 5.2.

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 5.2 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. They do not, however, affect the operation of the machine in any way.

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

When a LUN is deleted on a configured storage system, 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

Running the multipath command with the -ll option can cause the command to hang if one of the paths is on a blocking device. Note that the driver does not fail a request after some time if the device does not respond.

This is caused by the cleanup code, which waits until the path checker request either completes or fails. To display the current multipath state without hanging the command, use multipath -l instead.

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 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"

Upgrading pm-utils from a Red Hat Enterprise Linux 5.2 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, 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 at the time of the error will be lost. This generally results in a segmentation fault in the user application. Further, if opensm is running at the time the error occurs, then you need to manually restart it in order to resume proper operation.

Attempting to run sniff may result in an error. This is because some required packages are not installed with dogtail.

To prevent this from occurring, install the following packages manually:

It is not possible to configure layer 2 through system-config-network-gui.