Red Hat Enterprise Linux 6 Release Notes Release Notes for Red Hat Enterprise Linux 6 Copyright © 2010 Red Hat. The text of and illustrations in this document are licensed by Red Hat under a Creative Commons Attribution–Share Alike 3.0 Unported license ("CC-BY-SA"). An explanation of CC-BY-SA is available at http://creativecommons.org/licenses/by-sa/3.0/. In accordance with CC-BY-SA, if you distribute this document or an adaptation of it, you must provide the URL for the original version.
Release Notes Abstract The Release Notes document the major features and enhancements implemented in the Red Hat Enterprise Linux 6 release. 1. Introduction ........................................................................................................................... 2 2. Installer .................................................................................................................................. 2 3. File Systems ...................................................................
Installation Methods Further Reading 1 The Red Hat Enterprise Linux 6 Installation Guide provides detailed documentation of the installer and the installation process. 2.1. Installation Methods The installer provides three main interfaces to install Red Hat Enterprise Linux: kickstart, the graphical installer and the text-based installer. 2.1.1. Graphical Installer The Red Hat Enterprise Linux graphical installer steps the user through the major steps involved in preparing a system for installation.
Release Notes Figure 2. Partitioning Layout Choices The Installer allows storage devices to be specified as either install target devices or data storage devices prior to installation. Figure 3.
Creating Backup Passphrases During Installation 2.1.2. Kickstart Kickstart is an automated installation method that system administrators use to install Red Hat Enterprise Linux. Using kickstart, a single file is created, containing the answers to all the questions that would normally be asked during a typical installation.
Release Notes Note Currently, creating backup passphrases for encrypted devices during installation can only be achieved during a kickstart installation. More information on this new feature, including how to utilize this feature in a kickstart installation of Red Hat Enterprise Linux 6, refer to the Disk 2 Encryption appendix in the Installation Guide. 2.3. DVD Media Boot Catalog Entries The DVD media for Red Hat Enterprise Linux 6 include boot catalog entries for both BIOS- and UEFIbased computers.
Installation Logs Figure 5. Installation Error Reporting 2.5. Installation Logs To assist troubleshooting and debugging of installations, additional details are now included in log files produced by the installer. Further information on installation logs, and how to use them for 3 troubleshooting can be found in the following sections of the Installation Guide.
Release Notes 3.1. Fourth Extended Filesystem (ext4) Support The fourth extended filesystem (ext4) is based on the third extended filesystem (ext3) and features a number of improvements. These include support for larger file systems and larger files, faster and more efficient allocation of disk space, no limit on the number of subdirectories within a directory, faster file system checking, and more robust journaling. The ext4 file system is selected by default and is highly recommended. 3.2.
Dynamic Load Balancing with DM-Multipath Further Reading 9 The Storage Administration Guide features a chapter that covers I/O Limits in further detail. 4.2. Dynamic Load Balancing with DM-Multipath Device Mapper Multipathing (DM-Multipath) creates a single conceptual device from the multiple cables, switches and controllers that connect servers to storage arrays.
Release Notes 4.3.1.1. Merging Snapshots Red Hat Enterprise Linux 6 introduces the ability to merge a snapshot of a logical volume back into the origin logical volume. This allows system administrators to revert any changes that have occurred on a logical volume by merging back to the point preserved by a snapshot. For more information about the new snapshot merge feature, consult the lvconvert manpage. 4.3.1.2.
Package Management 6. Package Management 6.1. Strong Package Checksums RPM provides support for signed packages using strong hash algorithms such as SHA-256 in order to ensure package integrity and increase security. Red Hat Enterprise Linux 6 packages are transparently compressed with the XZ lossless compression library, which implements the LZMA2 compression algorithm for greater compression (thus reducing package size) and faster unpacking (when installing RPMs).
Release Notes Further Reading 17 The Cluster Suite Overview document provides an overview of Red Hat Cluster Suite for Red 18 Hat Enterprise Linux 6. Additionally, the High Availability Administration document describes the configuration and management of Red Hat cluster systems for Red Hat Enterprise Linux 6. 7.1. Corosync Cluster Engine Red Hat Enterprise Linux 6 utilizes the Corosync Cluster Engine for core cluster functionality. 7.2.
Security-Enhanced Linux (SELinux) identity and authentication services enables local caching of identities, allowing users to still identify in cases where the connection to the server is interrupted. SSSD supports many types of identity and authentication services, including: Red Hat Directory Server, Active Directory, OpenLDAP, 389, Kerberos and LDAP.
Release Notes Figure 6. Decrypting Data However, if the passphrase is misplaced, the encryption key cannot be used, and data on the encrypted storage device cannot be accessed. Red Hat Enterprise Linux 6 provides the ability to save encryption keys and create backup passphrases. This feature allows for the recovery of an encrypted volume (including the root device) even when the original passphrase is misplaced. 8.4.
Netlabel 9.2.2. Intra-Site Automatic Tunnel Addressing Protocol Red Hat Enterprise Linux 6 features support for the Intra-Site Automatic Tunnel Addressing Protocol (ISATAP). ISATAP is a protocol designed to assist in the transition from IPv4 to IPv6, by providing a mechanism to connect IPv6 routers and hosts over IPv4 network infrastructure. 9.3. Netlabel Netlabel is a new kernel-level feature in Red Hat Enterprise Linux 6 that provides network packet labeling services for Linux Security Modules (LSMs).
Release Notes 10.3. Multiple Display Support Red Hat Enterprise Linux 6 features enhanced support for workstations with multiple displays. When an additional display is attached to a machine, the graphics driver detects it and automatically adds it to the desktop. Conversely, when a display is unplugged, the graphics driver automatically removes it from the desktop. Note By default, the additional display is added in a spanning layout to the left of the current display.
Multiple Display Support 10.3.1. Display Preferences The new Display Preferences dialog provides the ability to further customize multiple display layouts. Figure 7. Display Preferences Dialog The new dialog provides the ability to instantly change the positioning, resolution, refresh rate and rotation settings for each individual display that is currently attached to a machine.
Release Notes 10.4. nouveau Driver for NVIDIA Graphics Devices Red Hat Enterprise Linux 6 features the new nouveau driver as default for NVIDIA graphics devices up to and including the NVIDIA GeForce 200 series. nouveau supports 2D and software video acceleration and kernel modesetting. Note The previous default driver for NVIDIA hardware (nv) is still available in Red Hat Enterprise Linux 6. 10.5. Internationalization 10.5.1.
Applications 10.6.2. Thunderbird 3 Red Hat Enterprise Linux 6 includes version 3 of the Mozilla Thunderbird email client, providing tabbed messaging, smart folders, and a message archive. For further details on new features in Thunderbird 23 3, refer to the Thunderbird Release Notes 10.6.3. OpenOffice.org 3.1 Red Hat Enterprise Linux 6 features OpenOffice.org 3.1, adding support for reading a wider range of file formats, including Microsoft Office OOXML format. Additionally, OpenOffice.
Release Notes 10.7. NetworkManager NetworkManager is the desktop tool that is used to set up, configure and manage a wide range of network connection types. Figure 9. NetworkManager In Red Hat Enterprise Linux 6, NetworkManager provides enhanced support for Mobile Broadband devices, IPv6 and added support for connecting to Bluetooth Personal Area Network (PAN) devices. 10.8. KDE 4.3 Red Hat Enterprise Linux 6 provides KDE 4.3 as an alternative desktop environment. KDE 4.
Release Documentation • Security • Tools and Performance • Clustering • Virtualization 11.1. Release Documentation Release Notes The Release Notes 25 document the major new features in Red Hat Enterprise Linux 6. Technical Notes 26 The Red Hat Enterprise Linux Technical Notes contains detailed information specific to this release, including: Technology Previews, package change details and known issues.
Release Notes administrators with intermediate experience in either Red Hat Enterprise Linux or Fedora distributions of Linux. Global File System 2 32 The Global File System 2 book provides information about configuring and maintaining Red Hat GFS2 (Global File System 2) for Red Hat Enterprise Linux 6. Logical Volume Manager Administration 33 The Logical Volume Manager Administration book describes the LVM logical volume manager, including information on running LVM in a clustered environment. 11.3.
High Availability consumption (for both server and laptop), and how each technique affects the overall performance of a system. Developer Guide 39 The Developer Guide describes the different features and utilities that make Red Hat Enterprise Linux 6 an ideal enterprise platform for application development. SystemTap Beginners Guide 40 The SystemTap Beginners Guide provides basic instructions on how to use SystemTap to monitor different subsystems of Red Hat Enterprise Linux in finer detail.
Release Notes 11.6. Virtualization Virtualization Guide 46 The Virtualization Guide details the process to install, configure and manage the virtualization technologies in Red Hat Enterprise Linux 6. 12. Kernel 12.1. Resource Control 12.1.1. Control Groups Control groups are a new feature of the Linux kernel in Red Hat Enterprise Linux 6. Each control group is a set of tasks on a system that have been grouped together to better manage their interaction with system hardware.
Error Reporting 12.3. Error Reporting 12.3.1. Advanced Error Reporting (AER) The kernel in Red Hat Enterprise Linux 6 features Advanced Error Reporting (AER). AER is a new kernel feature that provides enhanced error reporting for PCI-Express devices. 12.3.2. Kdump Auto Enablement Kdump is now enabled by default on systems with large amounts of memory. Specifically, kdump is enabled by default on: • systems with more than 4GB of memory on architectures with a 4KB page size (i.e.
Release Notes 12.5.2. Ftrace and perf Two new tools are available in Red Hat Enterprise Linux 6 to assist in analyzing kernel performance. Ftrace provides call graph style tracing for the kernel. The new perf tool monitors, logs and analyzes system hardware events. 12.6. General Kernel Updates 12.6.1. Physical Address Extension (PAE) The Physical Address Extension (PAE) is a feature implemented in modern x86 processors.
GNU Compiler Collection (GCC) Red Hat Enterprise Linux 6 features version 0.9.5 of OProfile, adding support for new Intel and AMD processors. 13.3. GNU Compiler Collection (GCC) The GNU Compiler Collection (GCC) includes, among others, C, C++, and Java GNU compilers and related support libraries. Red Hat Enterprise Linux 6 features version 4.4 of GCC, which includes the following features and enhancements: • Conformance to version 3.
Release Notes Python Scripting This updated version of GDB introduces the new Python API, allowing GDB to be automated using scripts written in the Python Programming Language. One notable feature of the Python API is the ability to format GDB output (normally referred to as pretty-printing) using Python scripts. Previously, pretty-printing in GDB was configured using a standard set of print settings.
Virtualization • Encrypted SMB transport between Samba client and server • Full support for Windows cross-forest, transitive trusts and one-way domain trusts • New NetApi remote management and winbind client C libraries • A new graphical user interface for joining Windows Domains Further Reading 49 Refer to the Deployment Guide Enterprise Linux 6. for further information on Samba configuration on Red Hat 15. Virtualization 15.1.
Release Notes 15.1.3. Storage • Indirect ring entries (spin locks) for the para-virtualized (virtio) driver improve block I/O performance and allows more concurrent I/O operations. • Virtualized storage devices can now be added and removed (hot plugged) from guests during runtime. • Support for block alignment storage topology awareness. Underlying storage hardware features and physical storage sector sizes (for example, 4KB sectors) are presented to guests.
Xen 15.1.10. Guest Device ABI Stability As part of the new qdev device model, the guest ABI is now stable and will be kept consistent for newer releases. The devices and device arrangements on guests will remain consistent in future updates. This feature resolves issues with some operating system activation processes. Note Red Hat Enterprise Linux 6 includes components providing functionality for the Simple Protocol for Independent Computing Environments (SPICE) remote display protocol.
Release Notes Important firstaidkit is considered a Technology Preview in Red Hat Enterprise Linux 6. 16.2. Bug Reporting 16.2.1. Installation Crash Reporting Red Hat Enterprise Linux 6 features enhanced installation crash reporting in the installer. Refer to Section 2.
Automated Bug Reporting Tool 16.3. Automated Bug Reporting Tool Red Hat Enterprise Linux 6 features the new Automated Bug Reporting Tool (ABRT). ABRT logs details of software crashes on a local system, and provides interfaces (both graphical and command line based) to report issues to Red Hat support. Figure 10. Automated Bug Reporting Tool 17. Web Servers and Services 17.1. Apache HTTP Web Server The Apache HTTP Server is a robust, commercial-grade open source Web server.
Release Notes Apache in Red Hat Enterprise Linux 6 features support for the Server Name Indication (SNI) protocol, which enables name-based virtual hosting over Secure Sockets Layer (SSL) connections. Additionally, support for the Web Server Gateway Interface (WSGI) has been added to Apache for this release, enabling the use of python web application frameworks that implement the WSGI standard. 17.2.
Revision History A. Revision History Revision 1-0 Wed Nov 10 2010 Ryan Lerch rlerch@redhat.