Red Hat ENTERPRISE LINUX 5.4 - RELEASE NOTES Release Note
1
Red Hat Enterprise
Linux 5.4
Release Notes
Release Notes for all architectures.
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Abstract
This document details the Release Notes for Red Hat Enterprise Linux 5.4.
1. Virtualization Updates .............................................................................................................. 2
2. Clustering Updates ................................................................................................................. 3
2.1. Fencing Improvements ................................................................................................. 4
3. Networking Updates ................................................................................................................ 5
4. Filesystems and Storage updates ............................................................................................ 5
5. Desktop Updates .................................................................................................................... 6
5.1. Advanced Linux Sound Architecture .............................................................................. 6
5.2. Graphics Drivers .......................................................................................................... 6
5.3. Laptop Support ............................................................................................................ 7
6. Tools Updates ......................................................................................................................... 7
7. Architecture Specific Support ................................................................................................... 8
7.1. i386 ............................................................................................................................. 8
7.2. x86_64 ........................................................................................................................ 9
7.3. PPC ............................................................................................................................ 9
7.4. s390 ............................................................................................................................ 9
8. Kernel Updates ..................................................................................................................... 11
8.1. General Kernel Feature Support .................................................................................. 11
8.2. General Platform Support ........................................................................................... 13
Release Notes
2
8.3. Driver Updates ........................................................................................................... 13
9. Technology Previews ............................................................................................................. 18
A. Revision History 19
This document contains the Release Notes for the Red Hat Enterprise Linux 5.4 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. For detailed documentation on all changes to Red Hat
Enterprise Linux for the 5.4 update, refer to the Technical Notes
1
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.
1
http://www.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5.4/html/Technical_Notes/
Clustering Updates
3
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 qspicemozilla 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.
Important
The virtio-win component is only available via the Red Hat Network, and is not included on
the physical Supplementary CD for Red Hat Enterprise Linux 5.4. For more information,
see the Red Hat Knowledgebase2.
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 Overview3 and
the Cluster Administration4 documents.
3
http://www.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/Cluster_Suite_Overview/index.html
4
http://www.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/Cluster_Administration/index.html
Release Notes
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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)5. Fencing support has also been added, as a Technology
Preview for Cisco MDS 9124 & Cisco MDS 9134 Multilayer Fabric Switches (BZ#480836).
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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.
The fence_scsi man page has been updated, detailing the following limitations:
The fence_scsi fencing agent requires a minimum of three nodes in the cluster to operate. For
an FC connected SAN devices, these must be physical nodes. SAN devices connected via iSCSI
may use virtual or physical nodes. In addition, fence_scsi cannot be used in conjunction
with qdisk.
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
5
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=485700
6
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=480836
Networking Updates
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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)7) 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)
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4. Filesystems and Storage 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)9. Support for the XFS file system has also been added to the
kernel for future product enablement (BZ#470845)10. 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)11.
Additionally, the Common Internet File System (CIFS) has been updated in the kernel (BZ#465143)12.
The ext4 file system (included in Red Hat Enterprise Linux as a Technology Preview) has also been
updated (BZ#485315)13.
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
7
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=499347
8
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=483708
9
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=457975
10
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=470845
11
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=296951
12
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=465143
13
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=485315
Release Notes
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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)
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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.
With this update, the dmraid logwatch-based email reporting feature has been moved from the
dmraid-events package into the new dmraid-events-logwatch package. Consequently,
systems that use this dmraid feature will need to complete the following manual procedure:
1. ensure the new 'dmraid-events-logwatch' package is installed.
2. un-comment the functional portion of the /etc/cron.d/dmeventd-logwatch crontab file.
(BZ#512833)
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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.
Important
the samba3x packages conflict with the samba-3.0 packages shipped with Red Hat
Enterprise Linux 5. To use the Technology Preview, it is recommended to perform a fresh
install that does not include the samba-3.0 packages, and then to install the samba3x
packages from the Supplementary media.
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.
14
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=469848
15
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=512833
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