Red Hat Enterprise Linux 4 Update 5 Release Notes

Red Hat Enterprise Linux 4 does not include support for ql2xfailover, as it has not been accepted upstream.

To implement multipathing, use mdadm instead. For more information about dm-multipath, consult its man page using the command man multipath.

During PCI probing, Red Hat Enterprise Linux 4 Update 5 attempts to use information obtained from MCFG (memory-mapped PCI configuration space). On AMD-systems, this type of access does not work on some buses, as the kernel cannot parse the MCFG table.

To work around this, add the parameter pci=conf1 or pci=nommconf on the kernel boot line in /etc/grub.conf. For example:

title Red Hat Enterprise Linux AS (2.6.9-42.0.2.EL)
        root (hd0,0)
        kernel /vmlinuz-2.6.9-42.0.2.EL ro root=/dev/VolGroup00/LogVol00 rhgb quiet pci=conf1
        initrd /initrd-2.6.9-42.0.2.EL.img

Doing this instructs the kernel to use PCI Conf1 access instead of MCFG-based access.

The up2date options --undo and list-rollbacks are now deprecated. Currently, the recommended method for performing a rollback is to use the Multi-state Rollback feature provided by the Provisioning entitlement on Red Hat Network. For more information about this, refer to http://www.redhat.com/rhn/rhndetails/provisioning/.

Alternatively, you can also downgrade an RPM manually. To do this, obtain the old RPM and run the following command:

rpm -Uvh --oldpackage --nosignature --nodigest <filename of old RPM>

Red Hat Enterprise Linux 4 Update 5 is now supported as a paravirtualized guest, but cannot be used as dom0.

At present, paravirtualization for Red Hat Enterprise Linux 4 Update 5 has the following issues:

Slow disk dump may be improved using the block_order parameter. This parameter specifies the I/O block size to be used when writing the dump. Testing has shown that the default value 2 works well for most adapters and system configurations.

Note that disk dumps on Megaraid hardware (in certain system platforms and under certain configurations) may be prohibitively slow. To address this, increase the value of the block_order parameter.

Larger block_order values consume more module memory. For more information about the block_order parameter, refer to /usr/share/doc/diskdumputils-<version>/README (replace <version> with the corresponding version of the diskdumputils package installed).

The iSeries ODBC Driver for Linux has been replaced by a new product -- the iSeries Access for Linux. This new product can be downloaded at the following link:

http://www.ibm.com/eserver/iseries/access/linux/

iSeries Access for Linux is the latest offering in the iSeries Access product line. It offers Linux-based access to iSeries servers. iSeries Access for Linux allows you to :

The ibmasm package is used to facilitate communication with the IBM Advance System Management PCI Adapter, also known as RSA I. If you are using the RSA II, you need to manually uninstall the ibmasm package after downloading the corresponding package for RSA II.

Systemtap provides free software (GPL) infrastructure to simplify the gathering of information about the running Linux system. This assists diagnosis of a performance or functional problem. With the help of systemtap, developers no longer need to go through the tedious and disruptive instrument, recompile, install, and reboot sequence that may be otherwise required to collect data.

The goal of the frysk project is to create an intelligent, distributed, always-on system monitoring and debugging tool that allows developers and system administrators to:

In Red Hat Enterprise Linux 4 Update 5 the frysk graphical user interface is a technology preview, whereas the frysk command line interface is fully supported.