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7. Technology Previews

Technology Preview features are currently not supported under Red Hat Enterprise Linux subscription services, may not be functionally complete, and are generally not suitable for production use. However, these features are included as a customer convenience and to provide the feature with wider exposure.
Customers may find these features useful in a non-production environment. Customers are also free to provide feedback and functionality suggestions for a Technology Preview feature before it becomes fully supported. Erratas will be provided for high-severity security issues.
During the development of a Technology Preview feature, additional components may become available to the public for testing. It is the intention of Red Hat to fully support Technology Preview features in a future release.

7.1. All Architectures

ALUA Mode on EMC Clariion
Explicit active-passive failover (ALUA) mode using dm-multipath on EMC Clariion storage is now available. This mode is provided as per T10 specifications, but is provided in this release only as a technology preview.
For more information about T10, refer to http://www.t10.org.
radeon_tp
The radeon_tp driver is now included in this release as a Technology Preview. This driver enables the ATI R500/R600 chipsets.
This driver also features the following capabilities:
  • Modesetting on R500/R600 chipsets
  • 2D acceleration on R500 chipsets
  • Shadow framebuffer acceleration on R600 chipsets
FreeIPMI
FreeIPMI is now included in this update as a Technology Preview. FreeIPMI is a collection of Intelligent Platform Management IPMI system software. It provides in-band and out-of-band software, along with a development library conforming to the Intelligent Platform Management Interface (IPMI v1.5 and v2.0) standards.
For more information about FreeIPMI, refer to http://www.gnu.org/software/freeipmi/
Frysk
The goal of the frysk project is to create an intelligent, distributed, always-on system monitoring and debugging tool that allows developers and system administrators to:
  • monitor running processes and threads (including creation and destruction events)
  • monitor the use of locking primitives
  • expose deadlocks
  • gather data
  • debug any given process by choosing it from a list or allowing frysk to open a source code (or other) window on a process that is crashing or misbehaving
This updated version of frysk includes the following new utilities:
  • fauxv
  • fdebuginfo
  • fdebugrpm
  • ferror
  • fexe
  • fmaps
In addition, ftrace can now perform signal and function symbol tracing. In previous releases, ftrace could only perform system call tracing.
frysk was introduced in Red Hat Enterprise Linux 5, and is still included in this release as a Technology Preview. For more information about frysk, refer to http://sources.redhat.com/frysk/.
TrouSerS and tpm-tools
TrouSerS and tpm-tools are included in this release to enable use of Trusted Platform Module (TPM) hardware.TPM hardware features include (among others):
  • Creation, storage, and use of RSA keys securely (without being exposed in memory)
  • Verification of a platform's software state using cryptographic hashes
TrouSerS is an implementation of the Trusted Computing Group's Software Stack (TSS) specification. You can use TrouSerS to write applications that make use of TPM hardware. tpm-tools is a suite of tools used to manage and utilize TPM hardware.
For more information about TrouSerS, refer to http://trousers.sourceforge.net/.
eCryptfs
eCryptfs is a stacked cryptographic file system for Linux. It mounts on individual directories in existing mounted lower file systems such as EXT3; there is no need to change existing partitions or file systems in order to start using eCryptfs.
eCryptfs stores cryptographic metadata in the header of each file written to the lower file system. This enables you to copy encrypted files between hosts or directly onto backup media. Files encrypted and copied in this manner can be decrypted with the proper key.
This release's version of eCryptfs provides several key management options, including protection based on passphrases and public keys. Below is a list of other fully functional features:
  • Interactive and non-interactive mounting.
  • Compatibility with SELinux.
  • Cryptographic metadata storage in both xattrs and file headers.
At present, the following issues still exist with eCryptfs:
  • direct_IO is not implemented.
  • Complex I/O patterns within the mmap implementation in eCryptfs may cause data corruption in some cases.
  • eCryptfs cannot be used for root file systems.
For more information about eCryptfs, refer to http://ecryptfs.sf.net. You can also refer to http://ecryptfs.sourceforge.net/README and http://ecryptfs.sourceforge.net/ecryptfs-faq.html for basic setup information.
GFS2
GFS2 is an incremental advancement of GFS. This update applies several significant improvements that require a change to the on-disk file system format. GFS file systems can be converted to GFS2 using the utility gfs2_convert, which updates the metadata of a GFS file system accordingly.
While much improved since its introduction in Red Hat Enterprise Linux 5, GFS2 remains a Technology Preview. Benchmark tests indicate faster performance on the following:
  • heavy usage in a single directory and faster directory scans (Postmark benchmark)
  • synchronous I/O operations (fstest benchmark test indicates improved performance for messaging applications like TIBCO)
  • cached reads, as there is no longer any locking overhead
  • direct I/O to preallocated files
  • NFS file handle lookups
  • df, as allocation information is now cached
In addition, GFS2 also features the following changes:
  • journals are now plain (though hidden) files instead of metadata. Journals can now be dynamically added as additional servers mount a file system.
  • quotas are now enabled and disabled by the mount option quota=<on|off|account>
  • quiesce is no longer needed on a cluster to replay journals for failure recovery
  • nanosecond timestamps are now supported
  • similar to ext3, GFS2 now supports the data=ordered mode
  • attribute settings lsattr() and chattr() are now supported via standard ioctl()
  • file system sizes above 16TB are now supported
  • GFS2 is a standard file system, and can be used in non-clustered configurations
Stateless Linux
Stateless Linux is a new way of thinking about how a system should be run and managed, designed to simplify provisioning and management of large numbers of systems by making them easily replaceable. This is accomplished primarily by establishing prepared system images which get replicated and managed across a large number of stateless systems, running the operating system in a read-only manner (refer to /etc/sysconfig/readonly-root for more details).
In its current state of development, the Stateless features are subsets of the intended goals. As such, the capability remains as Technology Preview.
Red Hat recommends that those interested in testing stateless code read the HOWTO at http://fedoraproject.org/wiki/StatelessLinux/HOWTO and join stateless-list@redhat.com.
The enabling infrastructure pieces for Stateless Linux were originally introduced in Red Hat Enterprise Linux 5.
AIGLX
AIGLX is a Technology Preview feature of the otherwise fully supported X server. It aims to enable GL-accelerated effects on a standard desktop. The project consists of the following:
  • A lightly modified X server.
  • An updated Mesa package that adds new protocol support.
By installing these components, you can have GL-accelerated effects on your desktop with very few changes, as well as the ability to enable and disable them at will without replacing your X server. AIGLX also enables remote GLX applications to take advantage of hardware GLX acceleration.
iSCSI Target
The Linux target (tgt) framework allows a system to serve block-level SCSI storage to other systems that have a SCSI initiator. This capability is being initially deployed as a Linux iSCSI target, serving storage over a network to any iSCSI initiator.
To set up the iSCSI target, install the scsi-target-utils RPM and refer to the instructions in:
  • /usr/share/doc/scsi-target-utils-[version]/README
  • /usr/share/doc/scsi-target-utils-[version]/README.iscsi
Replace [version] with the corresponding version of the package installed.
For more information, refer to man tgtadm.
FireWire
The firewire-sbp2 module is still included in this update as a Technology Preview. This module enables connectivity with FireWire storage devices and scanners.
At present, FireWire does not support the following:
  • IPv4
  • pcilynx host controllers
  • multi-LUN storage devices
  • non-exclusive access to storage devices
In addition, the following issues still exist in FireWire:
  • a memory leak in the SBP2 driver may cause the machine to become unresponsive.
  • a code in this version does not work properly in big-endian machines. This could lead to unexpected behavior in PowerPC.

7.2. x86 Architectures

mac80211 802.11a/b/g WiFi protocol stack (mac80211)
The mac80211 stack (formerly known as the devicescape/d80211 stack) enables the iwlwifi 4965GN wireless driver for Intel Wifi Link 4965 hardware. This stack allows certain wireless devices to connect to any Wi-Fi network.
Although the stack is already accepted upstream, the stability of this stack is yet to be verified through testing. As such, this stack is included in this release as a Technology Preview.

7.3. x86-64 Architectures

mac80211 802.11a/b/g WiFi protocol stack (mac80211)
The mac80211 stack (formerly known as the devicescape/d80211 stack) enables the iwlwifi 4965GN wireless driver for Intel Wifi Link 4965 hardware. This stack allows certain wireless devices to connect to any Wi-Fi network.
Although the stack is already accepted upstream, the stability of this stack is yet to be verified through testing. As such, this stack is included in this release as a Technology Preview.