6.0 Beta 1 Release Notes

[이누기]

출처: http://www.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6-Beta/html-single/Beta_Release_Notes/

내용을 대충 훓터 봤는데 다양하게 조금씩 다양한 부분에서 바뀌어 있었습니다.

특히 하나의 미디어로 여러 아키텍쳐를 지원한다는 내용부터

파일시스템의 지원 부분 확대(storage,ext4,xfs등) , LVM을 컨트롤 할 수 있는 API의 지원, 전원관리 기능 추가(tuned,powertop), 클러스터링 옵션지원 보안부분 강화, IPV6의 확대 지원,무선인터넷을 자동으로 잡을 수 있는 부분까지 다양하네요..

또한 firstaidkit 라는 자동 시스템 복구툴을 제공하고, 특히 클러스터에서는 SCSI의 lun이 바뀌던 문제로 인한 부분이 향상되었다고 하며, KVM GUEST가 서비스로 운영될 수 있다고 합니다.

Red Hat Enterprise Linux 6 Beta Release Notes

Release Notes and New Features in Red Hat Enterprise Linux 6 Beta 1

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Abstract

The Release Notes document the major features and enhancements implemented in the Red Hat Enterprise Linux 6 release.

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1. Introduction

2. Installer

2.1. Installation Methods

2.2. Creating Backup Passphrases During Installation

2.3. DVD Media Boot Catalog Entries

2.4. Installation Crash Reporting

2.5. Installation Logs

3. File Systems

3.1. Fourth Extended Filesystem (ext4) Support

3.2. XFS

3.3. Block Discard — enhanced support for thinly provisioned LUNs and SSD devices

3.4. Network File System (NFS)

3.5. FS-Cache

3.6. btrfs

4. Storage

4.1. Storage Input/Output (I/O) Limits

4.2. Dynamic Load Balancing with DM-Multipath

4.3. Logical Volume Manager (LVM)

4.4. LVM Application Programming Interface (API)

5. Power Management

5.1. powertop

5.2. tuned

6. Clustering

6.1. Corosync Cluster Engine

6.2. Unified Logging Configuration

6.3. Staged Cluster Upgrades

6.4. Cluster Administration

6.5. General Cluster Improvements

7. Security

7.1. System Security Services Daemon (SSSD)

7.2. Security-Enhanced Linux (SELinux)

7.3. Backup Passphrases for Encrypted Storage Devices

7.4. sVirt

7.5. Enterprise Security Client

8. Networking

8.1. Multiqueue Networking

8.2. Internet Protocol version 6 (IPv6)

8.3. Netlabel

8.4. Generic Receive Offload

8.5. Wireless Support

9. Desktop

9.1. Graphical Startup

9.2. Suspend and Resume

9.3. Multiple Display Support

9.4. nouveau Driver for NVIDIA Graphics Devices

9.5. Applications

9.6. NetworkManager

9.7. KDE 4.3

10. Documentation

10.1. Release Documentation

10.2. Installation and Deployment

10.3. Security

10.4. Tools & Performance

10.5. Clustering

10.6. Virtualization

11. Kernel

11.1. Resource Control

11.2. Scalability

11.3. Error Reporting

11.4. Power Management

11.5. Analyzing Kernel Performance

11.6. General Kernel Updates

12. Compiler and Tools

12.1. SystemTap

12.2. OProfile

12.3. GNU Compiler Collection (GCC)

12.4. GNU C Library (glibc)

12.5. GNU Project debugger (GDB)

13. Interoperability

13.1. Samba

14. Virtualization

14.1. Kernel-based Virtual Machine (KVM)

14.2. XEN

15. Supportability and Maintenance

15.1. firstaidkit System Recovery Tool

15.2. Bug Reporting

15.3. Automated Bug Reporting Tool

16. Web Servers and Services

16.1. Apache HTTP Web Server

16.2. PHP: Hypertext Preprocessor (PHP)

16.3. memcached

17. Databases

17.1. PostgreSQL

17.2. MySQL

18. Architecture Specific Notes

A. Reporting Issues for Red Hat Enterprise Linux 6 Beta

A.1. Automated Bug Reporting Tool (ABRT)

A.1.1. ABRT in a Graphical Environment

A.1.2. ABRT in a Command Line Enviroment

A.2. SELinux AVC Denial Messages

A.3. How to Report Documentation Issues

B. Recommended Limits

B.1. Minimum System Requirements

B.2. Virtualization

B.3. Clustering

C. Deprecated and Discontinued Features

C.1. Deprecated Drivers

C.2. Discontinued Drivers

C.3. Deprecated Packages

C.4. Discontinued Packages

D. Known Issues

D.1. Installation

D.2. Architecture Specific

D.2.1. System z

D.2.2. IBM Power (64-bit)

D.3. Kernel Known Issues

D.4. Desktop Known Issues

D.5. Virtualization

D.6. Other Known Issues

E. Revision History

1.  Introduction

Red Hat is pleased to announce the availability of Red Hat Enterprise Linux 6 Beta. Red Hat Enterprise Linux 6 Beta is the next generation of Red Hat's comprehensive suite of operating systems, designed for mission-critical enterprise computing and certified by top enterprise software and hardware vendors.

Figure 1. Red Hat Enterprise Linux Beta

This release is available as a single kit on the following architectures:

• i386
• AMD64/Intel64
• System z
• IBM Power (64-bit)

In this release, Red Hat brings together improvements across the server, systems and the overall Red Hat open source experience.

Note

Third-party content, and content that does not fall under the GNU General Public License (GPL) is not available in Red Hat Enterprise Linux 6 Beta. This content will be available on the Red Hat Enterprise Linux 6 General Availability (GA) date via the Supplementary channel.

2. Installer

2.1. Installation Methods

2.2. Creating Backup Passphrases During Installation

2.3. DVD Media Boot Catalog Entries

2.4. Installation Crash Reporting

2.5. Installation Logs

The Red Hat Enterprise Linux installer (also known as anaconda) assists in the installation of Red Hat Enterprise Linux 6 Beta. This section of the release notes provides an overview of the new features implemented in the installer for Red Hat Enterprise Linux 6 Beta.

Further Reading

The Red Hat Enterprise Linux 6 Beta 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 6 Beta graphical installer steps the user through the major steps involved in preparing a system for installation.

The Red Hat Enterprise Linux 6 Beta installation GUI introduces major usability enhancements for disk partitioning and storage configuration.

Early in the installation process, the user is now given the choice of Basic Storage Devices or Specialized Storage Devices. Basic Storage Devices typically do not need any additional configuration settings before the device is usable.

A new interface has been implemented for configuring Specialized Storage Devices. Firmware RAID devices, Fibre Channel over Ethernet (FCoE) devices, multipath devices, and other storage area network (SAN) devices can now be easily configured using the new interface.

Figure 2. Specialized Storage Devices Configuration

The interface for choosing partitioning layouts has been enhanced, providing detailed descriptions and diagrams for each default partitioning layout

Figure 3. Partitioning layout choices

The Installer allows storage devices to be specified as either install target devices or data storage devices prior to installation.

Figure 4. Specifying Storage Devices

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.

Red Hat Enterprise Linux 6 Beta introduces improvements to the validation of kickstart files, allowing the installer to capture issues with kickstart file syntax before an installation commences.

2.1.3. Text-based Installer

The text-based installer is provided primarily for systems with limited resources. The text-based installer has been simplified, permitting installation to the default disk layouts, and installation of new and updated packages.

Figure 5. text-based installer

2.2. Creating Backup Passphrases During Installation

The installer in Red Hat Enterprise Linux 6 Beta provides the ability to save encryption keys and create backup passphrases. This feature is discussed in futher detail in Section 7.3, “Backup Passphrases for Encrypted Storage Devices”

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 Beta, refer to Appendix C. Disk Encryption of the Installation Guide.

2.3. DVD Media Boot Catalog Entries

The DVD media for Red Hat Enterprise Linux 6 Beta include boot catalog entries for both BIOS- and UEFI-based computers. This allows the media to boot systems based on either firmware interface. (UEFI is the Unified Extensible Firmware Interface, a standard software interface initially developed by Intel and now managed by the Unified EFI Forum. It is intended as a replacement for the older BIOS firmware.)

Important

Some systems with very old BIOS implementations will not boot from media which include more than one boot catalog entry. Such systems will not boot from a Red Hat Enterprise Linux 6 Beta DVD but may be bootable using a USB drive or over a network using PXE.

Note

UEFI and BIOS boot configurations differ significantly from each other and are not interchangeable. An installed instance of Red Hat Enterprise Linux 6 Beta will not boot if the firmware it was configured for is changed. You cannot, for example, install the operating system on a BIOS-based system and then boot the installed instance on a UEFI-based system.

2.4. Installation Crash Reporting

Red Hat Enterprise Linux 6 Beta features enhanced installation crash reporting in the installer. If the installer encounters an error during the installation process, details of the error are reported to the user.

Figure 6. installation error reporting

The details of the error can be instantly reported to the Red Hat Bugzilla bug tracking website, or in cases where there is no internet connectivity, saved locally to disk.

Figure 7. Sending to Bugzilla

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 troubleshooting can be found in the following sections of the Installation Guide.

• Troubleshooting Installation on an Intel or AMD System
• Troubleshooting Installation on an IBM POWER System
• Troubleshooting Installation on an IBM System z System

3. File Systems

3.1. Fourth Extended Filesystem (ext4) Support

3.2. XFS

3.3. Block Discard — enhanced support for thinly provisioned LUNs and SSD devices

3.4. Network File System (NFS)

3.5. FS-Cache

3.6. btrfs

Further Reading

The Storage Administration Guide provides further instructions on how to effectively manage file systems on Red Hat Enterprise Linux 6 Beta. Additionally, the Global File System 2 document details specific information on configuring and maintaining Red Hat Global File System 2 for Red Hat Enterprise Linux 6 Beta.

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. XFS

XFS is a highly scalable, high-performance file system which was originally designed at Silicon Graphics, Inc. It was created to support filesystems up to 16 exabytes (approximately 16 million terabytes), files up to 8 exabytes (approximately 8 million terabytes) and directory structures containing tens of millions of entries).

XFS supports metadata journaling, which facilitates quicker crash recovery. The XFS file systems can also be defragmented and resized (i.e. enlarged) while mounted and active.

Note

The kernel modules that enable XFS support in Red Hat Enterprise Linux 6 Beta are only built against the x86_64 kernel.

3.3. Block Discard — enhanced support for thinly provisioned LUNs and SSD devices

Filesystems in Red Hat Enterprise Linux 6 Beta use the new block discard feature to allows a storage device to be informed when the filesystem detects that portions of a device (also known as blocks) are no longer in active use. While few storage devices feature block discard capabilities, newer solid state drives (SSDs) utlize this feature to optimize internal data layout and invoke proactive wear levelling. Additionally, some high end SCSI devices use block discard information to help implement thinly provisioned LUNs.

3.4. Network File System (NFS)

A Network File System (NFS) allows remote hosts to mount file systems over a network and interact with those file systems as though they are mounted locally. This enables system administrators to consolidate resources onto centralized servers on the network. Red Hat Enterprise Linux 6 Beta supports NFSv2, NFSv3, and NFSv4 clients. Mounting a file system via NFS now defaults to NFSv4.

Additional improvements have been made to the NFS in Red Hat Enterprise Linux 6 Beta, providing enhanced support over Internet Protocol version 6 (IPv6)

3.5. FS-Cache

FS-Cache is a new feature in Red Hat Enterprise Linux 6 Beta that enables networked file systems (e.g. NFS) to have a persistent cache of data on the client machine.

Note

FS-Cache is considered a Technology Preview in Red Hat Enterprise Linux 6 Beta

3.6. btrfs

Btrfs is under development as a file system capable of addressing and managing more files, larger files, and larger volumes than the ext2, ext3, and ext4 file systems. Btrfs is designed to make the file system tolerant of errors, and to facilitate the detection and repair of errors when they occur. It uses checksums to ensure the validity of data and metadata, and maintains snapshots of the file system that can be used for backup or repair.

Btrfs is still experimental

Red Hat Enterprise Linux 6 Beta includes Btrfs as a technology preview to allow you to experiment with this file system. You should not choose Btrfs for partitions that will contain valuable data or that are essential for the operation of important systems.

4. Storage

4.1. Storage Input/Output (I/O) Limits

4.2. Dynamic Load Balancing with DM-Multipath

4.3. Logical Volume Manager (LVM)

4.4. LVM Application Programming Interface (API)

4.1. Storage Input/Output (I/O) Limits

Some storage devices have the ability relay capability information (e.g. input/output limits) back to the operating system. The Red Hat Enterprise Linux 6 Beta provides the ability to read and utilize this information, and optimize how data is read and written from storage devices.

Further Reading

Chapter 19 of the Storage Administation Guide 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. This enables centralized management of connection devices (also known as paths) and makes it possible to balance loads over all available paths.

DM-Multipath in Red Hat Enterprise Linux 6 Beta introduces two new options when dynamically balancing load over paths. Paths can now be dynamically selected depending on either the queue size of each path or previous I/O time data.

Further Reading

The DM Multipath book provides information on using the Device-Mapper Multipath feature of Red Hat Enterprise Linux 6 Beta

4.3. Logical Volume Manager (LVM)

Volume management creates a layer of abstraction over physical storage by creating logical storage volumes. This provides greater flexibility over just using physical storage directly. In Red Hat Enterprise Linux 6 Beta, manages logical volumes using the Logical Volume Manager (LVM).

Important

system-config-lvm is a graphical user interface provided in Red Hat Enterprise Linux to manage logical volumes. The functionality provided by system-config-lvm is in the process of transitioning to a more maintainable tool named gnome-disk-utility. As a result, Red Hat will be very selective in updating system-config-lvm. As gnome-disk-utility reaches feature parity with system-config-lvm, Red Hat reserves the right to remove system-config-lvm during the life of Red Hat Enterprise Linux 6.

Further Reading

The Logical Volume Manager Administration document describes the LVM logical volume manager, including information on running LVM in a clustered environment.

4.3.1. LVM Mirror Improvements

LVM supports mirrored volumes. By creating mirrored logical volumes, LVM ensures that data written to an underlying physical volume is mirrored onto a separate physical volume.

4.3.1.1. Snapshots of Mirrors

The LVM snapshot feature provides the ability to create backup images of a logical volume at a particular instant without causing a service interruption. When a change is made to the original device (the origin) after a snapshot is taken, the snapshot feature makes a copy of the changed data area as it was prior to the change so that it can reconstruct the state of the device. Red Hat Enterprise Linux 6 Beta introduces the ability to take a snapshot of a mirrored logical volume.

4.3.1.2. Merging Snapshots

Red Hat Enterprise Linux 6 Beta 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.

4.3.1.3. Four-Volume Mirrors

LVM in Red Hat Enterprise Linux 6 Beta supports creating a logical volume with up to four mirrors.

4.3.1.4. Mirroring mirror logs

LVM maintains a small log (on a separate device) which it uses to keep track of which regions are in sync with the mirror or mirrors. Red Hat Enterprise Linux 6 Beta provides the ability to mirror this log device.

4.4. LVM Application Programming Interface (API)

Red Hat Enterprise Linux 6 Beta features the new LVM application programming interface (API) as a Technology Preview. This API is used to query and control certain aspects of LVM.

5. Power Management

5.1. powertop

5.2. tuned

Further Reading

The Power Management Guide provides information on effectively managing power consumption on Red Hat Enterprise Linux 6.

5.1. powertop

The introduction of the tickless kernel in Red Hat Enterprise Linux 6 Beta (refer to Section 11.4.2, “Tickless Kernel”) allows the CPU to enter the idle state more frequently, reducing power consumption and improving power management. The new powertop tool provides the ability to identify specific components of kernel and userspace applications that frequently wake up the CPU. powertop was used in development to identify and tune many applications in this release, reducing unnecessary CPU wake up by a factor of 10.

5.2. tuned

tuned is a system tuning daemon that monitors system components and dynamically tunes system settings. Utilizing ktune (the static mechanism for system tuning), tuned can monitor and tune devices (e.g. hard disk drives and ethernet devices). Red Hat Enterprise Linux 6 Beta also introduces diskdevstat for monitoring disk operations and netdevstat for monitoring network operations.

6. Clustering

6.1. Corosync Cluster Engine

6.2. Unified Logging Configuration

6.3. Staged Cluster Upgrades

6.4. Cluster Administration

6.5. General Cluster Improvements

Clusters are multiple computers (nodes) working in concert to increase reliability, scalability, and availability to critical production services. Clustering using Red Hat Enterprise Linux 6 can be deployed in a variety of configurations to suit varying needs for performance, high-availability, load balancing, and file sharing.

Further Reading

The Cluster Suite Overview document provides an overview of Red Hat Cluster Suite for Red Hat Enterprise Linux 6. Additionally, the Cluster Administration document describes the configuration and management of Red Hat cluster systems for Red Hat Enterprise Linux 6.

6.1. Corosync Cluster Engine

Red Hat Enterprise Linux 6 Beta utilizes the Corosync Cluster Engine for core cluster functionality.

6.2. Unified Logging Configuration

The various daemons that clustering employs now utilize a shared unified logging configuration. This allows system administrators to enable, capture and read cluster system logs via a single command in the cluster configuration.

6.3. Staged Cluster Upgrades

Red Hat Enterprise Linux 6 Beta features the ability to run cluster components in compatibility mode, enabling newer cluster components to interact with the cluster components from Red Hat Enterprise Linux 5. This feature allows system administrators to upgrade clusters, minimizing down time.

Important

Upgrading a cluster in this manner should be undertaken with great care. It is highly recommended that a cluster upgrade be attempted on a non-production cluster first. Additionally, it is recommended to work directly with Red Hat Support to validate an upgrade plan before undertaking it.

6.4. Cluster Administration

Conga is an integrated set of software components that provides centralized configuration and management of Red Hat clusters and storage. One of the primary components of Conga is luci, a server that runs on one computer and communicates with multiple clusters and computers. In Red Hat Enterprise Linux 6 Beta the web interface that is used to interact with luci has been redesigned.

6.5. General Cluster Improvements

In addition to the features and improvements detailed above, the following features and enhancements to clustering have been implemented for Red Hat Enterprise Linux 6 Beta

• Enhanced support for Internet Protocol version 6 (IPv6)
• SCSI persistent reservation fencing support is improved.
• Virtualized KVM guests can now be run as managed services.

7. Security

7.1. System Security Services Daemon (SSSD)

7.2. Security-Enhanced Linux (SELinux)

7.3. Backup Passphrases for Encrypted Storage Devices

7.4. sVirt

7.5. Enterprise Security Client

Further Reading

The Security Guide assists users and administrators in learning the processes and practices of securing workstations and servers against local and remote intrusion, exploitation and malicious activity.

7.1. System Security Services Daemon (SSSD)

The System Security Services Daemon (SSSD) is a new feature in Red Hat Enterprise Linux 6 Beta that implements a set of services for central management of identity and authentication. Centralizing 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.

Further Reading

The Deployment Guide contains a section that describes how to install and configure the System Security Services Daemon (SSSD), and how to use the features that it provides.

7.2. Security-Enhanced Linux (SELinux)

Security-Enhanced Linux (SELinux) adds Mandatory Access Control (MAC) to the Linux kernel, and is enabled by default in Red Hat Enterprise Linux 6 Beta. A general purpose MAC architecture needs the ability to enforce an administratively-set security policy over all processes and files in the system, basing decisions on labels containing a variety of security-relevant information.

SELinux AVC denial messages

To report SELinux AVC denial messages that may be encountered during beta testing, please refer to Appendix A, Reporting Issues for Red Hat Enterprise Linux 6 Beta .

7.2.1. Confined Users

Traditionally, SELinux is used to define and control how an application interacts with the system. SELinux in Red Hat Enterprise Linux 6 Beta introduces a set of policies that allows system administrators to control what particular users can access on a system.

7.2.2. Sandbox

SELinux in Red Hat Enterprise Linux 6 Beta features the new security sandbox feature. The security sandbox adds a set of SELinux policies that enables a system administrator to run any application within a tightly confined SELinux domain. Using the sandbox, system administrators can test the processing of untrusted content without damaging the system.

7.2.3. X Access Control Extension (XACE)

The X Window System (commonly refered to a "X") provides the base framework for displaying the graphical user interface (GUI) on Red Hat Enterprise Linux 6 Beta. This release features the new X Access Control Extension (XACE), which permits SELinux to access decisions made within X, specifically, controlling information flow between window objects.

7.3. Backup Passphrases for Encrypted Storage Devices

Red Hat Enterprise Linux provides the ability to encrypt the data on storage devices, assisting in the prevention of unauthorized access of the data. Encryption is achieved by transforming the data into a format that can only be read using a specific encryption key. This key — which is created during the installation process, and protected by a passphrase — is the only way to decrypt the encrypted data.

Figure 8. 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 Beta 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.

7.4. sVirt

libvirt is a C language application programming interface (API) for managing and interacting with the virtualization capabilities of Red Hat Enterprise Linux 6 Beta. In this release, libvirt features the new sVirt component. sVirt integrates with SELinux, providing security mechanisms to prevent unauthorized access of guests and hosts in a virtualized environment.

7.5. Enterprise Security Client

The Enterprise Security Client (ESC) is a simple GUI that allows Red Hat Enterprise Linux to manage smart cards and tokens. New smart cards can be formatted and enrolled, meaning that new keys are generated and certificates requested for the smart card automatically. The smart card lifecycle can be managed, as well, so that lost smart cards can have their certificates revoked and expired certificates can be renewed. The ESC works in conjunction with a larger public-key infrastructure management product, either Red Hat Certificate System or Dogtag PKI.

8. Networking

8.1. Multiqueue Networking

8.2. Internet Protocol version 6 (IPv6)

8.3. Netlabel

8.4. Generic Receive Offload

8.5. Wireless Support

8.1. Multiqueue Networking

Every data package transferred over a network device represents processing which must be completed by a CPU. The low-level network implementation in Red Hat Enterprise Linux 6 Beta now allows network device drivers to divide network packet processing across multiple queues. Dividing these processes allows a system to better utilize the multiple processors and CPU cores present on modern systems.

8.2. Internet Protocol version 6 (IPv6)

The next-generation Internet Protocol version 6 (IPv6) specification is designed as the successor to Internet Protocol version 4 (IPv4). IPv6 Specifies a wide range of improvements over IPv4, including: expanded addressing capabilites, flow labeling and simplified header formats.

8.2.1. Mobile IPv6

Red Hat Enterprise Linux 6 Beta features enhanced support for mobile IPv6 capabilities as defined by the RFC 3775 draft specification. The main goal of RFC 3775 is to set up a protocol to ensure that a mobile device is reachable even when it connects to the internet from different physical locations.

8.2.2. Optimistic Duplicate Address Detection

Duplicate Address Detection (DAD) is a feature of the Neighbor Discovery Protocol portion of IPv6. Specifically, DAD is tasked with checking if an IPv6 address is already being used. Red Hat Enterprise Linux features Optimistic Duplicate Address Detection, a speed optimization of DAD.

8.2.3. Intra-Site Automatic Tunnel Addressing Protocol

Red Hat Enterprise Linux 6 Beta 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.

8.3. Netlabel

Netlabel is a new kernel-level feature in Red Hat Enterprise Linux 6 Beta that provides network packet labeling services for Linux Security Modules (LSMs). Labeling data packets using netlabel allows an LSM to better enforce security requirements on incoming network packets.

8.4. Generic Receive Offload

The low-level network implementation in Red Hat Enterprise Linux 6 Beta features Generic Receive Offload (GRO) support. The GRO system increases the performance of inbound network connections by reducing the amount of processing done by the 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.

8.5. Wireless Support

Red Hat Enterprise Linux 6 Beta contains enhanced support for wireless networking and devices. Support for the wireless local area networking using the IEEE 802.11 set of standards has been improved, with added support for 802.11n based wireless networking.

9. Desktop

9.1. Graphical Startup

9.2. Suspend and Resume

9.3. Multiple Display Support

9.4. nouveau Driver for NVIDIA Graphics Devices

9.5. Applications

9.6. NetworkManager

9.7. KDE 4.3

9.1. Graphical Startup

Red Hat Enterprise Linux 6 Beta introduces a new, seamless graphical boot sequence that commences immediately after the hardware has initialized.

Figure 9. Graphical Boot Screen

The new graphical boot sequence provides the user with simple visual feedback on the progress of the system boot, and seamlessly switches to the login screen. The Red Hat Enterprise Linux 6 Beta graphical boot sequence is enabled by the Kernel Modesetting feature and is available on ATI, Intel and NVIDIA graphics hardware.

Note

System Administrators are still able to view detailed progress of the boot sequence by pressing the F11 key at any time during the graphical boot.

9.2. Suspend and Resume

Suspend and resume is a current feature in Red Hat Enterprise Linux that allows a machine to be placed into and out of a low power state. The new kernel modesetting feature enables enhanced support for the suspend and resume feature. Previously, graphics hardware was suspended and resumed via userspace applications. In Red Hat Enterprise Linux 6 Beta, this functionality has moved into the kernel, providing a more reliable mechanism for enabling low power mode.

9.3. Multiple Display Support

Red Hat Enterprise Linux 6 Beta 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 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.

The automatic detection of additional displays is useful in situations where displays are added and removed frequently (e.g. setting up a laptop with an external projector)

9.3.1. Display Preferences

The new Display Preferences dialog provides the ability to further customize multiple display layouts.

Figure 10. 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.

9.4. nouveau Driver for NVIDIA Graphics Devices

Red Hat Enterprise Linux 6 Beta 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 Beta.

9.5. Applications

The majority of applications on the Red Hat Enterprise Linux 6 Beta desktop have been updated. The following section documents the most notable updates.

9.5.1. Firefox

Red Hat Enterprise Linux 6 Beta introduces version 3.5 of the Mozilla Firefox web browser.

Figure 11. Mozilla Firefox 3.5

For details on the new features in Firefox, refer to the Firefox Release Notes

9.5.2. Thunderbird 3

Red Hat Enterprise Linux 6 Beta 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 3, refer to the Thunderbird Release Notes

9.5.3. OpenOffice.org 3.1

Red Hat Enterprise Linux 6 Beta features OpenOffice.org 3.1, adding support for reading a wider range of file formats, including Microsoft Office OOXML format. Additionally, OpenOffice.org has improved file locking support and has the ability to render graphics using anti-aliasing.

Figure 12. OpenOffice.org 3.1

Full details on all the features in this version of OpenOffice.org are available in the OpenOffice.org Release Notes .

9.6. NetworkManager

NetworkManager is the desktop tool that is used to setup, configure and manage a wide range of network connection types.

Figure 13. NetworkManager

In Red Hat Enterprise Linux 6 Beta, NetworkManager provides enhanced support for Mobile Broadband devices, IPv6 and added support for connecting to Bluetooth Personal Area Network (PAN) devices.

9.7. KDE 4.3

Red Hat Enterprise Linux 6 Beta provides KDE 4.3 as an alternative desktop enviroment.

Figure 14. KDE 4.3

10. Documentation

10.1. Release Documentation

10.2. Installation and Deployment

10.3. Security

10.4. Tools & Performance

10.5. Clustering

10.6. Virtualization

Documentation for Red Hat Enterprise Linux 6 Beta comprises of 18 separate documents. Each of these documents belong to one or more of the following subject areas:

• Release Documentation
• Installation and Deployment
• Security
• Tools and Performance
• Clustering
• Virtualization

Note

In addition to documenting the Beta release of Red Hat Enterprise Linux 6, the documentation should also be considered in a Beta or Draft status. If an issue is found in the Beta documentation, please refer to Section A.3, “How to Report Documentation Issues”

10.1. Release Documentation

Release Notes

The Release Notes document the major new features that are implemented in Red Hat Enterprise Linux 6 Beta.

Migration Guide

The Red Hat Enterprise Linux Migration Guide documents migration from Red Hat Enterprise Linux 5 to Red Hat Enterprise Linux 6.

10.2. Installation and Deployment

Installation Guide

The Installation Guide documents relevant information regarding the installation of Red Hat Enterprise Linux 6 Beta

Deployment Guide

The Deployment Guide documents relevant information regarding the deployment, configuration and administration of Red Hat Enterprise Linux 6 Beta.

Storage Administration Guide

The Storage Administration Guide provides instructions on how to effectively manage storage devices and file systems on Red Hat Enterprise Linux 6. It is intended for use by system administrators with intermediate experience in either Red Hat Enterprise Linux or Fedora distributions of Linux.

Global File System 2

The Global File System 2 book provides information about configuring and maintaining Red Hat GFS2 (Red Hat Global File System 2) for Red Hat Enterprise Linux 6 Beta.

Logical Volume Manager Administration

The Logical Volume Manager Administration book describes the LVM logical volume manager, including information on running LVM in a clustered environment.

10.3. Security

Security Guide

The Security Guide is designed to assist users and administrators in learning the processes and practices of securing workstations and servers against local and remote intrusion, exploitation and malicious activity.

SELinux User Guide

The SELinux User Guide covers the management and use of Security-Enhanced Linux for those with minimal or no experience with the framework. It serves as an introduction to SELinux and explains the terms and concepts in use.

Managing Confined Services

The Managing Confined Services guide is designed to assist advanced users and administrators when using and configuring Security-Enhanced Linux (SELinux). It is focused on Red Hat Enterprise Linux and describes the components of SELinux as they pertain to services an advanced user or administrator might need to configure. Also included are real-world examples of configuring these services and demonstrations of how SELinux complements their operation.

10.4. Tools & Performance

Resource Management Guide

The Resource Management Guide documents tools and techniques for managing system resources on Red Hat Enterprise Linux 6 Beta.

Power Management Guide

The Power Management Guide explains how to manage power consumption on Red Hat Enterprise Linux 6 systems effectively. This document discusses different techniques that lower power consumption (for both server and laptop), and how each technique affects the overall performance of a system.

Developer Guide

The Developer Guide describes the different features and utilities that make Red Hat Enterprise Linux 6 an ideal enterprise platform for application development.

10.5. Clustering

Cluster Suite Overview

The Cluster Suite Overview document provides an overview of Red Hat Cluster Suite for Red Hat Enterprise Linux 6.

Cluster Administration

The Cluster Administration document describes the configuration and management of Red Hat cluster systems for Red Hat Enterprise Linux 6.

Virtual Server Administration

The Virtual Server Administration book discusses the configuration of high-performance systems and services with Red Hat Enterprise Linux 6 Beta and the Linux Virtual Server (LVS) system.

DM Multipath

The DM Multipath book provides information on using the Device-Mapper Multipath feature of Red Hat Enterprise Linux 6 Beta.

10.6. Virtualization

Virtualization Guide

The Virtualization Guide details the process to install, configure and manage the virtualization technologies in Red Hat Enterprise Linux 6 Beta.

11. Kernel

11.1. Resource Control

11.2. Scalability

11.3. Error Reporting

11.4. Power Management

11.5. Analyzing Kernel Performance

11.6. General Kernel Updates

11.1. Resource Control

11.1.1. Control Groups

Control groups are a new feature of the Linux kernel in Red Hat Enterprise Linux 6 Beta. Each control group is a set of tasks on a system that have been grouped together to better manage their interaction with system hardware. Control groups can be tracked to monitor the system resources that they use. Additionally, system administrators can use control group infrastructure to allow or to deny specific control groups access to system resources such as memory, CPUs (or groups of CPUs), networking or the scheduler. Management of control groups in userspace is provided by libcgroup, enabling system administrators to create new control groups, start new processes in a specific control group or set control group parameters.

Note

Control Groups and other resource management features are discussed in detail in the Red Hat Enterprise Linux 6 Resource Management Guide

11.1.2. Linux (NameSpace) Container [LXC]

Linux (NameSpace) Containers [LXC] is a Technology Preview feature in Red Hat Enterprise Linux 6 Beta that provides isolation of resources assigned to one or more processes. A process is assigned a separate user permission, networking, filesystem name space from its parent.

11.2. Scalability

11.2.1. Completely Fair Scheduler (CFS)

A process (or task) scheduler is a specific kernel subsystem that is responsible for assigning the order in which processes are sent to the CPU. The kernel (version 2.6.32) shipped in Red Hat Enterprise Linux 6 Beta replaces the O(1) scheduler with the new Completely Fair Scheduler (CFS). The CFS implements the fair queuing scheduling algorithm.

11.2.2. Virtual Memory Pageout Scalability

Implemented by the kernel, virtual memory presents applications with a single, contiguous block of memory addresses. The reality underlying this presentation is complex, with actual physical addresses commonly fragmented and even paged out to much slower devices such as fixed disks. The virtual memory addresses are organized by the kernel into standard units called pages. The kernel in Red Hat Enterprise Linux 6 Beta features enhanced management of virtual memory pages, reducing the processing load required on systems with large amounts of physical memory.

11.3. Error Reporting

11.3.1. Advanced Error Reporting (AER)

The kernel in Red Hat Enterprise Linux 6 Beta features Advanced Error Reporting (AER). AER is a new kernel feature that provides enhanced error reporting for PCI-Express devices.

11.4. Power Management

11.4.1. Aggressive Link Power Management (ALPM)

The kernel in Red Hat Enterprise Linux 6 Beta feature support for Aggressive Link Power Management (ALPM). ALPM is a power-saving technique that helps the disk save power by setting a SATA link to the disk to a low-power setting during idle time (i.e. when there is no I/O). ALPM automatically sets the SATA link back to an active power state once I/O requests are queued to that link.

11.4.2. Tickless Kernel

Previously the kernel implemented a timer that periodically queried the system to check if there were any outstanding tasks to process. Consequently, the CPU would remain in an active state, consuming unnecessary power. The kernel in Red Hat Enterprise Linux 6 Beta enables the new tickless kernel feature, replacing the periodic timer interrupts with on-demand interrupts. The tickless kernel allows a CPU to enter longer sleep states when idle, and wake only when a task is queued for processing.

11.5. Analyzing Kernel Performance

11.5.1. Performance Counter for Linux (PCL)

The Linux Performance Counter infrastructure provides an abstraction of performance counter hardware capabilities, such as instructions executed, cachemisses, or branches mis-predicted. PCL provides per-task and per-CPU counters, and adds event capabilities on top of these counters. Performance counter information can be used to profile kernel functions and events, and assist in the analysis of kernel performance issues.

11.5.2. Ftrace and perf

Two new tools are available in Red Hat Enterprise Linux 6 Beta to assist in analyzing kernel performance. Ftrace provides call graph style tracing for the kernel. The new perf tool monitor, logs and analyzes system hardware events.

11.6. General Kernel Updates

11.6.1. Physical Address Extension (PAE)

The Physical Address Extension (PAE) is a feature implemented in modern x86 processors. PAE extends memory addressing capabilities, allowing more than 4 gigabytes (GB) of random access memory (RAM) to be used. The default kernel shipped with the i386 architecture version of Red Hat Enterprise Linux 6 Beta is PAE enabled.

11.6.2. Loadable Firmware Files

Firmware files for which there is no appropriately licensed source code have been removed from the Red Hat Enterprise Linux 6 kernel. Modules that require loadable firmware now use a kernel interface to request firmware from userspace.

12. Compiler and Tools

12.1. SystemTap

12.2. OProfile

12.3. GNU Compiler Collection (GCC)

12.4. GNU C Library (glibc)

12.5. GNU Project debugger (GDB)

12.1. SystemTap

SystemTap is a tracing and probing tool that allows users to study and monitor the activities of the operating system (particularly, the kernel) in fine detail. It provides information similar to the output of tools like netstat, ps, top, and iostat; however, SystemTap is designed to provide more filtering and analysis options for collected information.

Red Hat Enterprise Linux 6 Beta 1 features SystemTap version 1.1, which introduces many new features and enhancements, including:

• Improved support for user-space probing.
• Support for probing C++ programs with native C++ syntax.
• A more secure script-compile server.
• The new unprivileged mode, allowing non-root users to use SystemTap.

Important

Unprivileged mode is new and experimental. The stap-server facility on which it relies is undergoing work for security improvements and should be deployed with care on a trustworthy network.

12.2. OProfile

OProfile is a system-wide profiler for Linux systems. The profiling runs transparently in the background and profile data can be collected at any time.

Red Hat Enterprise Linux 6 Beta features version 0.9.5 of OProfile, adding support for new Intel and AMD processors.

12.3. 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 Beta features version 4.4 of GCC, which includes the following features and enhancements:

• Conformance to version 3.0 of the Open Multi-Processing (OpenMP) application programming interface (API).
• Additional C++ libraries to utilize OpenMP threads
• Futher imlementations of the next ISO C++ standard draft (C++0x)
• Introduction of variable tracking assignments to improve debugging using the GNU Project Debugger (GDB) and SystemTap.

More information about the improvements implemented in GCC 4.4 is available from the GCC website.

12.4. GNU C Library (glibc)

The GNU C Library (glibc) packages contain the standard C libraries used by multiple programs on Red Hat Enterprise Linux. These packages contains the standard C and the standard math libraries. Without these two libraries, the Linux system cannot function properly.

Red Hat Enterprise Linux 6 Beta features version 2.11 of glibc, providing many features and enhancements, including:

• An enhanced dynamic memory allocation (malloc) behaviour enabling higher scalability across many sockets and cores. This is achieved by assigning threads their own memory pools and by avoiding locking in some situations. The amount of additional memory used for the memory pools (if any) can be controlled using the environment variables MALLOC_ARENA_TEST and MALLOC_ARENA_MAX. MALLOC_ARENA_TEST specifies that a test for the number of cores is performed once the number of memory pools reaches this value. MALLOC_ARENA_MAX sets the maximum number of memory pools used, regardless of the number of cores.
• Improved efficiency when using condition variables (condvars) with priority inheritance (PI) mutual exclusion (mutex) operations by utilizing support in the kernel for PI fast userspace mutexes.
• Optimized string operations on the x86_64 architecture.
• The getaddrinfo() function now has support for the Datagram Congestion Control Protocol (DCCP), the UDP-Lite protocol. Additionally, getaddrinfo() now has the ability to look up IPv4 and IPv6 addresses simultaneously,

12.5. GNU Project debugger (GDB)

The GNU Project debugger (normally referred to as GDB) debugs programs written in C, C++, and other languages by executing them in a controlled fashion, and then printing out their data. Red Hat Enterprise Linux 6 Beta features version 7.0 of GDB.

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. The ability to create custom pretty-printer scripts gives the user control of the way GDB displays information for specific applications. Red Hat Enterprise Linux will ship with a complete suite of pretty-printer scripts for the GNU Standard C++ Library (libstdc++).

Enhanced C++ support

Support for the C++ programming language in GDB has been improved. Notable improvements include:

• Many improvements to expression‎ parsing.
• Better handling of type names.
• The need for extraneous quoting has nearly been eliminated
• "next" and other stepping commands work properly even when the inferior throws an exception.
• GDB has a new "catch syscall" command. This can be used to stop the inferior whenever it makes a system call.

Independent thread debugging

Thread execution now permits debugging threads individually and independently of each other; enabled by new settings "set target-async" and "set non-stop".

13. Interoperability

13.1. Samba

13.1. Samba

Samba is a suite of programs which use NetBIOS over TCP/IP (NetBT) to enable the sharing of files, printers and other information (such as directories of available files and printers). This package provides a Server Message Block or SMB server (also known as a Common Internet File System or CIFS server) which can provide network services to SMB/CIFS clients.

Red Hat Enterprise Linux 6 Beta provides the following significant enhancements to Samba:

• Internet Protocol version 6 support (IPv6)
• Support for Windows 2008 (R2) trust relationships.
• Support for Windows 7 domain members.
• Support for Active Directory LDAP signing/sealing policy.
• Improvements for libsmbclient
• Better support for Windows management tools (mmc and User Manager)
• Automatic machine password changes as domain member
• New registry based configuration layer
• 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

Refer to the Deployment Guide for Futher information on Samba configuration on Red Hat Enterprise Linux 6 Beta.

14. Virtualization

14.1. Kernel-based Virtual Machine (KVM)

14.2. XEN

14.1. Kernel-based Virtual Machine (KVM)

Red Hat Enterprise Linux 6 Beta 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.

14.1.1. New KVM Features

KVM in Red Hat Enterprise Linux 6 Beta introduces the following new features:

• Added support for High Precision Event Timer (HPET) clock emulation on the x86 architecture
• Support for hot-plugging emulated PCI devices
• Support for MSI-X
• Added support for network booting via gPXE (formerly Etherboot)
• irq, mmio, mmu tracing
• virtio-console - which serves as a virtual communication channel between a host and a guest.

SPICE

Red Hat Enterprise Linux 6 Beta includes components providing functionality for the Simple Protocol for Independent Computing Environments (SPICE) remote display protocol. These components are are only supported for use in conjunction with Red Hat Enterprise Virtualization products and are not guaranteed to have a stable ABI. The components will be updated to synchronize with functional requirements of Red Hat Enterprise Virtualization products. Migration to future releases may require manual operations on a per-system basis.

14.1.2. Performance Improvements

• Many bug fixes and performance enhancements for the qcow2 format.
• The block layer in qemu now uses aio and preadv/pwritev calls, providing faster emulation
• Indirect ring entries in virtio, improving block I/O performance
• reduced CPU overhead by caching internal vmcs variables, reduced wakeups and finer grained locking.
• Large page backed memory
• Kernel Shared Memory (KSM) full swapping
• SR-IOV

14.1.3. Guest stable ABI

As part of the new qdev device model, the guest ABI is now stable and will be kept accurate over releases. PCI devices can be mapped statically into PCI slots. It is possible to control the existence/removal of all devices and features.

14.2. XEN

Red Hat Enterprise Linux 6 Beta is supported as a Xen guest for the x86 and x86_64 architectures. Additionally, Red Hat Enterprise Linux 6 Beta can be used as both a Xen paravirtualized (PV) guest or as a Fully virtualized (FV) guest with PV drivers. Due to paravirtualized operations (pv-ops) being included in the kernel, the same kernel can be used for either mode of operation as well as for bare metal. There is no support for using Red Hat Enterprise Linux 6 Beta as a Xen host.

Further Reading

The Virtualization Guide details the process to install, configure and manage the virtualization technologies in Red Hat Enterprise Linux 6 Beta.

15. Supportability and Maintenance

15.1. firstaidkit System Recovery Tool

15.2. Bug Reporting

15.3. Automated Bug Reporting Tool

15.1. firstaidkit System Recovery Tool

Red Hat Enterprise Linux 6 Beta includes the new firstaidkit system recovery tool. By automating common recovery processes, firstaidkit provides an interactive environment to assists in the troubleshooting and recovery of a system that boots incorrectly. Additionally, system administrators are able to create custom automated recovery processes using the firstaidkit plugin infrastructure.

Important

firstaidkit is considered a Technology Preview in Red Hat Enterprise Linux 6 Beta.

15.2. Bug Reporting

15.2.1. Installation Crash Reporting

Red Hat Enterprise Linux 6 Beta features enhanced installation crash reporting in the installer. Refer to Section 2.4, “Installation Crash Reporting”

15.3. Automated Bug Reporting Tool

Red Hat Enterprise Linux 6 Beta 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 instantly open a ticket in the Red Hat Bugzilla bug tracking website.

Figure 15. Automated Bug Reporting Tool

16. Web Servers and Services

16.1. Apache HTTP Web Server

16.2. PHP: Hypertext Preprocessor (PHP)

16.3. memcached

16.1. Apache HTTP Web Server

The Apache HTTP Server is a robust, commercial-grade open source Web server. Red Hat Enterprise Linux 6 Beta includes the Apache HTTP Server 2.2.14 as well as a number of server modules designed to enhance its functionality.

Apache in Red Hat Enterprise Linux 6 Beta 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.

16.2. PHP: Hypertext Preprocessor (PHP)

PHP is an HTML-embedded scripting language commonly used with the Apache HTTP Web server. In Red Hat Enterprise Linux, PHP has now supports the Alternative PHP Cache (APC).

16.3. memcached

memcached is a high-performance distributed object caching server that is designed to increase the performance of dynamic web applications by reducing database load. memcached is a new feature in this release, and provides bindings for C, PHP, Perl and Python programming languages.

17. Databases

17.1. PostgreSQL

17.2. MySQL

17.1. PostgreSQL

PostgreSQL is an advanced Object-Relational database management system (DBMS). The postgresql packages include the client programs and libraries needed to access a PostgreSQL DBMS server.

Red Hat Enterprise Linux 6 Beta features version 8.4 of PostgreSQL

17.2. MySQL

MySQL is a multi-user, multi-threaded SQL database server. It consists of the MySQL server daemon (mysqld) and many client programs and libraries.

This release features version 5.1 of MySQL. For a list of all enhancements that this version provides, refer to the MySQL Release Notes

18. Architecture Specific Notes

Red Hat Enterprise Linux 6 is architecturally complete, and all supported architectures are now available.

Red Hat Enterprise Linux 6 will not provide support for the Intel? Itanium? architecture. All Itanium-related development will be incorporated into Red Hat Enterprise Linux 5 exclusively. Through March 2014, Red Hat Enterprise Linux 5 will provide support, deliver new features, and enable new Itanium hardware in accordance with the published Red Hat Enterprise Linux product life-cycle. In addition, extended support for Red Hat Enterprise Linux 5 for Itanium is available up to March 2017 from selected OEMs.

A.  Reporting Issues for Red Hat Enterprise Linux 6 Beta

A.1. Automated Bug Reporting Tool (ABRT)

A.1.1. ABRT in a Graphical Environment

A.1.2. ABRT in a Command Line Enviroment

Red Hat Enterprise Linux 6 Beta introduces the new Automated Bug Reporting Tool (refer to Section 15.3, “Automated Bug Reporting Tool”) to provide and easy mechanism for reporting issues.

A.1.1. ABRT in a Graphical Environment

To use ABRT in a graphical desktop environment (i.e. the GNOME or KDE desktops), the abrt-desktop package must be installed. In the event the system encounters a failure, the abrt-desktop tool will present a notification that an application has crashed and attempt to generate a backtrace to review. Once ABRT is opened, you have the option to report the issue to the Red Hat Bugzilla bug tracking website.

A.1.2. ABRT in a Command Line Enviroment

In a command-line only environment ABRT is invoked using the abrt-cli command. To see a list of issues captured by ABRT, use the command:

abrt-cli --get-list

To report an issue, use the command:

	abrt-cli --report <uuid>

ABRT will attempt to generate a backtrace for you to review. Next, double check the report, and remove any sensitive data from the backtrace. Upon exiting the editor, ABRT will attempt to report the issue to the Red Hat Bugzilla bug tracking website. Bugzilla credentials will be required to complete the report submission process.

A.2. SELinux AVC Denial Messages

If AVC denial messages are encountered while using Red Hat Enterprise Linux 6 Beta, please report these messages on the Red Hat Bugzilla bug tracking website. If ipsec_t is the source domain that SELinux is denying, collect all the AVC denial messages that are generated and add them to the bug report. To continue testing, the offending process can be placed into permissive mode using the command:

semanage permissive -a <OBJECT>

Alternatively, rules can be added to SELinux by generating a local policy, for example

grep ipsec /var/log/audit2allow -M myipsec
semodule -i mypsec.pp

A.3. How to Report Documentation Issues

If you find a typographical error in the Red Hat Enterprise Linux 6 Beta documentation, or if you have thought of a way to make the documentation better, we would love to hear from you! Please submit a report in Bugzilla: http://bugzilla.redhat.com/ against the product Red Hat Enterprise Linux.

When submitting a bug report, be sure to mention the manual's identifier (e.g. "doc-Installation_Guide" for the Installation Guide) and version number: 6. If you have a suggestion for improving the documentation, try to be as specific as possible when describing it. If you have found an error, please include the section number and some of the surrounding text so we can find it easily.

B. Recommended Limits

The following requirements and recommendations

B.1. Minimum System Requirements

	i386, AMD64/Intel64	IBM Power (64-bit)	System z
Minimum	1GB per logical CPU	2GB	1GB
Recommended	2GB	4GB	-

Table B.1. Memory Requirements

	i386, AMD64/Intel64	IBM Power (64-bit)	System z
Minimum	1GB	1GB	1GB
Recommended	5GB	5GB	5GB

Table B.2. Storage Requirements

B.2. Virtualization

	All Architectures
Minimum	1GB per logical CPU
Maximum	64GB

Table B.3. Virtualization Memory Requirements (per guest)

B.3. Clustering

The maximum cluster node count under Red Hat Enterprise Linux 6 Beta is 16.

C. Deprecated and Discontinued Features

C.1. Deprecated Drivers

Listed below are the older device drivers that have improved replacements in Red Hat Enterprise Linux 6 Beta. These drivers are still shipped, but are likely to be discontinued in subsequent releases.

• aacraid
• aic7xxx
• i2o
• ips
• mptlan
• sym53c8xx

C.2. Discontinued Drivers

Listed below are device drivers have been discontinued in Red Hat Enterprise Linux 6 Beta.

• aic7xxx_old (replaced by aic7xxx)
• atp870u
• cpqarray
• DAC960
• dc395x
• gdth
• hfs
• hfsplus
• linuxwacom (replaced by xorg-x11-drv-wacom)
• megaraid (replaced by megaraid_mbox)
• net/tokenring/
• paride
• qla1280
• sound/core/oss
• sound/drivers/opl3/*
• sound/pci/nm256

C.3. Deprecated Packages

Listed below are older packages that have improved replacements in Red Hat Enterprise Linux 6 Beta. These packages are still shipped, but are likely to be discontinued in subsequent releases.

• kmod-gfs (GFS1)
• gfs-utils (GFS1)
• gcj
• qt3
• hal

C.4. Discontinued Packages

The following table details the packages that have been discontinued in Red Hat Enterprise Linux 6 Beta.

Discontinued Package	Replaced By
amanda	bacula
beecrypt	nss/openssl (new API)
crash-spu-commands
dhcpv6	dhcp
dhcpv6-client	dhclient
elfspe2
gnbd	iSCSI
gnome-vfs	gvfs
ipsec-tools	openswan (new API)
kmod-gnbd	iSCSI
lam	openmpi
linuxwacom	xorg-x11-drv-wacom
libspe2
libspe2-devel
mkinitrd	dracut
nss_ldap	nss_pam_ldapd, pam_ldap
openmotif-2.2	openmotif-2.3
spu-tools
syslog	rsyslog
SysVinit	upstart
system-config-bind	no direct replacement (refer to the Migration Guide )
system-config-boot	no direct replacement (refer to the Migration Guide )
system-config-cluster	luci
system-config-httpd	no direct replacement (refer to the Migration Guide )
system-config-netboot	no direct replacement (refer to the Migration Guide )
system-config-nfs	no direct replacement (refer to the Migration Guide )
system-config-samba	no direct replacement (refer to the Migration Guide )
system-config-mail	no direct replacement (refer to the Migration Guide )
system-config-display	the gnome-display-properties dialog
system-config-lvm	gnome-disk-util, lvm
system-config-netboot	cobbler (available via RHN Satellite)
system-config-network	NetworkManager
system-config-rootpassword	system-config-users
switchdesk	The new user session selection functionality in GDM and KDM
vixie-cron	cronie

Table C.1. Discontinued Packages

D. Known Issues

Upgrading from previous pre-release versions

Upgrading to Red Hat Enterprise Linux 6 Beta from previous pre-release versions of Red Hat Enterprise Linux 6 is not supported. If an upgrade of this type is attempted issues may be encountered while upgrading Java/OpenJDK packages. To work around this, manually remove the old packages and reinstall.

D.1. Installation

• On the Power PC architecture, if the /boot directory is on a separate partition on an MD array (or the root directory "/" is on an MD array and there is no separate partition for /boot), anaconda fails to correctly configure the bootloader. To work around this issue, place the /boot directory on a separate partition that is not part of an MD array. Alternatively, after installation, the yaboot bootloader can be installed and configured manually using tty2 or rescue media.
• Installing to a RAID boot drive on a system containing drives that are not members of the RAID may result in the default boot device selection for the bootloader to be set incorrectly. To work around this issue, edit the bootloader drive order during installation to choose the RAID drive. Alternatively, if a kickstart installation is performed, the option bootloader --driverorder should be used.
• Installation of Red Hat Enterprise Linux 6 Beta as a KVM guest will fail if the default filesystem layout (LVM) is used. To work around this issue, create non-LVM partitions for the root ("/"), boot and swap filesystems.
• i386 UEFI machines which do not allow you to manually select BIOS booting will not work correctly. This issue will be resolved in a future pre-release version of Red Hat Enterprise Linux 6.
• The cio ignore implementation has not been completed for zFCP devices. In order to avoid installation problems on those devices the images/generic.prm file needs have the following entry instead:

  root=/dev/ram0 ro ip=off ramdisk_size=40000
  

• In previous versions of Red Hat Enterprise Linux, users were presented with a network interface configuration screen during installation. The user could configure basic TCP/IP network settings for each network interface for the target system. Starting with Red Hat Enterprise Linux 6, the installer uses NetworkManager for network interface configuration, and existing interface configuration screen was removed from the installer.
  In this Beta release, if a a network-based install is performed, the installer will configure the target system with the network settings used during installation. Otherwise, users will notice there is no way in the graphical or text installer to configure their network interfaces on the target system. In future pre-release versions of Red Hat Enterprise Linux 6, the user will be able to access the NetworkManager configuration interface during installation.
  To work around this limitation, the 'network' command of a kickstart installation can be used to configure the network interfaces on the target system. Alternatively, during an interactive installation, switch to tty2 at the end of installation (Ctrl+Alt+F2) and customize the necessary ifcfg-eth* file(s) in /mnt/sysimage/etc/syconfig/network-scripts.
• Installation of Red Hat Enterprise Linux 6 Beta may fail if attempting to install on storage devices that have been previously encrypted. To work around this issue, manually clear the partition table of the device, or manually create a new partition layout on the device.
• Red Hat Enterprise Linux 6 Beta may fail to boot after appearing to install correctly. There is no known workaround for this issue. To assist in the characterization and debugging of the issue, please enter a bug into the Red Hat Bugzillaand include details of the storage configuration (including SAN details).
• Installation of Red Hat Enterprise Linux 6 Beta will fail if the install disk is a multipath device.
• The installer in Red Hat Enterprise Linux 6 Beta is unable to format DASD volumes detected as 'unformatted' during device discovery. If a system has unformatted DASD volumes that need to be used during installation, format these volumes by using CPFMTXA in z/VM or the dasdfmt command in Linux.
  To achieve this log in to the system over SSH as the root user when the installer welcome screen appears. Use the dasdfmt command to inspect /proc/dasd/devices file, and issue the following command for each line containing the word 'unformatted':

  dasdfmt -y -P -d cdl -b 4096 /dev/dasdX
  

  Where /dev/dasdX is the unformatted DASD volume listed in /proc/dasd/devices. Once you have run dasdfmt on all unformatted volumes, return to the installer and continue.

  Important

  This procedure must be completed before proceeding past the installer welcome screen.
• In Red Hat Enterprise Linux 5, if a package was available for both the main and the compatiblity arch, both architectures of the package are installed by default. In Red Hat Enterprise Linux 6 Beta, only the package for the primary arch is installed by default. This behavior can be changed by setting 'multilib_policy=all' in /etc/yum.conf. Packages can still be installed by specifying the architecture in the yum install command, or the kickstart package list; for example, 'yum install libstdc++.i686'.

D.2. Architecture Specific

D.2.1. System z

D.2.2. IBM Power (64-bit)

D.2.1. System z

The minimum hardware requirement to run Red Hat Enterprise Linux Beta is IBM System z9 (or better). The system may not IPL (i.e. boot) on earlier System Z hardware (e.g. z900 or z990)

D.2.2. IBM Power (64-bit)

• When network booting an IBM Power5 series system, you may encounter an error such as:

  DEFAULT CATCH!, exception-handler=fff00300
  

  If the path that locates the kernel and ramdisk is greater than 63 characters long, it will overflow a firmware buffer and the firmware will drop into the debugger.
  Power6 and Power7 firmware includes a correction for this problem.
• On some machines yaboot may not boot, returning the error message:

  Cannot load ramdisk.image.gz: Claim failed for initrd memory at 02000000 rc=ffffffff
  

  To work around this issue, change real-base from to c00000. Real-base can be obtained from OpenFirmware prompt with the printenv command and set with setenv command.
• yaboot does not correctly detect iSCSI devices, returning the message "Not a valid ELF image". This issue will be resolved in a later pre-release version of Red Hat Enterprise Linux 6
• cgexec tool does not work on Power PC architectures

D.3. Kernel Known Issues

• There are several situations where warning messages such as the following may occur when the kernel RPM is installed:

    W: Possible missing firmware aic94xx-seq.fw for module aic94xx.ko
    W: Possible missing firmware ql8100_fw.bin for module qla2xxx.ko
  

  The severity of these messages depends on the hardware. In some cases the lack of loadable firmware will cause the adapter to be non-functional. (This is the case in the first example. The Adaptec firmware is not available because of licensing issues.) You may be able to obtain a firmware file from the hardware vendor. Place this file in /lib/firmware/.
  In other cases, the warning message indicates that the driver is capable of using loadable firmware if a firmware file is present, but it is not required to make the adapter operational. (This is the case in the second example, where the adapter has non-volatile firmware on board.) (Bug 529700).
• Calgary IOMMU default detection has been disabled in this release. If you require Calgary IOMMU support add 'iommu=calgary' as a boot parameter.
• The memory controller in Red Hat Enterprise Linux 6 beta may encounter stability issues when under heavy stress testing or memory pressure.
• The i686 debug kernel may crash on some systems when starting the udev service.
• Systems configured with Intel 82578DM NICs may not be recognized during boot/install resulting in driver load failure, (driver probe fails with error -2).

D.4. Desktop Known Issues

• Systems using Intel graphics devices may encounter abnormal display output flickering. To work around this issue, add i915.powersave=0 to the kernel boot parameters.

D.5. Virtualization

• Red Hat Enterprise Linux 6 Beta can not be installed as a fully virtualized Xen guest.
• As root, attempting to install a new guest (using a URL as the installation source) using virt-install or virt-manager may fail, returning an error message similar to:

  could not load kernel '/var/lib/libvirt/boot/virtinst-vmlinuz.bmav1g':
  Permission denied
  

  To work around this issue, launch virt-manager as a regular user. Alternatively, if the source URL points to an ISO file, manually fetch the file and point to it directly.
• This pre-release version of Red Hat Enterprise Linux 6 does not support PCI device assignment to KVM guests using libvirt.

D.6. Other Known Issues

• The winbind component of the Samba package is unable to retrieve user and group information from a Windows 2008 R2 Active Directory Server if all communication occurs over IPv6. "wbinfo -t" will return an error indicating that the RPC call failed and due to failure to validate trust secret. To work around this issue, use IPv4.
• Red Hat Enterprise Linux 6 Beta features Dovecot version 1.2. The configuration files used by dovecot 1.2 are significantly different from those found in dovecot 1.0.x, the version shipped previous releases of Red Hat Enterprise Linux. Specifically, /etc/dovecot.conf has been split into /etc/dovecot/dovecot.conf and /etc/dovecot/conf.d/*.conf
• Enabling user authentication against an LDAP server using the authconfig --enableldapauth does not correctly set up the /etc/nslcd.conf configuration file. Consequently, LDAP users will be denied access to the system. To work around this issue, remove the line containing pam_password md5 from the /etc/nslcd.conf file.
• The intr / nointr NFS mount option is deprecated. Only SIGKILL can interrupt a pending NFS operation on these kernels. If specified, this mount option can be ignored to provide backwards compatibility with older kernels.

E. Revision History

Revision History
Revision 0.2	Mon Mar 08 2010	Ryan Lerch
Release Notes for the Beta 1 Release of Red Hat Enterprise Linux 6
Revision 0.1	Mon Oct 19 2009	Ryan Lerch
Alpha 2 Notes Release