The kernel in Red Hat Enterprise Linux 6.6 has been enhanced to enable user space to respond to certain SCSI Unit Attention conditions received from SCSI devices via the udev event mechanism. The supported Unit Attention conditions are:

The default udev rules for the supported Unit Attention conditions are provided by the libstoragemgmt RPM package. The udev rules are located in the /lib/udev/rules.d/90-scsi-ua.rules file.

The default rules handle the REPORTED LUNS DATA HAS CHANGED unit attention. Additional example rules are present to enumerate the other events that the kernel can generate. Note that the default rules do not automatically remove logical unit numbers (LUNs) that are no longer present on the SCSI target.

Because SCSI Unit Attention conditions are only reported in response to a SCSI command, no conditions are reported if no commands are actively being sent to the SCSI device.

The default behavior can be customized by modifying or removing the udev rules. If the libstoragemgmt RPM package is not installed, the default rules are not present. If no udev rules are present for those events, no action is taken, but the events themselves are still generated by the kernel.

Red Hat Enterprise Linux 6.6 includes the Open vSwitch kernel module as an enabler for Red Hat's layered products. Open vSwitch is supported only in conjunction with products that contain the accompanying user-space utilities. Please note that without these required user-space utilities, Open vSwitch will not function and cannot be enabled for use. For more information, please refer to the following Knowledge Base article: https://access.redhat.com/knowledge/articles/270223.

Starting with Red Hat Enterprise Linux 6.6, the High Performance Networking (HPN) Add-On is no longer be available as a separate product. Instead, the functionality found in the HPN Add-On has been integrated into the base product and delivered as part of the Red Hat Enterprise Linux base channel.

In addition to including the HPN functionality into the base Red Hat Enterprise Linux 6 product, the RDMA over Converged Ethernet (RoCE) implementation has also been updated. RoCE uses Global Identifier or GID-based addressing for node-to-node communication. Previously, GIDs were encoded based on the Ethernet interface's MAC address along with the VLAN ID (if used). Under certain circumstances, the compute entity that runs the RoCE protocol is not aware that its traffic is VLAN-tagged. The compute entity can then sometimes create or assume a wrong GID, which can result in connectivity problems. The updated RoCE implementation resolves this problem by changing the way the RoCE GIDs are encoded, and instead bases them off the IP addresses of the Ethernet interface. All systems that use the RoCE protocol need to be upgraded to Red Hat Enterprise Linux 6.6 to ensure connection reliability due to this change in the wire protocol format.

Please refer to this Red Hat Knowledge Base article for additional information: https://access.redhat.com/site/articles/971333.

The scap-security-guide package has been included in Red Hat Enterprise Linux 6.6 to provide security guidance, baselines, and associated validation mechanisms that use Security Content Automation Protocol (SCAP). SCAP Security Guide contains the necessary data to perform system security compliance scans regarding prescribed security policy requirements; both a written description and an automated test (probe) are included. By automating the testing, SCAP Security Guide provides a convenient and reliable way to verify system compliance on a regular basis.

New hyperv-daemons packages have been added to Red Hat Enterprise Linux 6.6. The new packages include the Hyper-V KVP daemon, previously provided by the hypervkvpd package, the Hyper-V VSS daemon, previously provided by the hypervvssd package, and the hv_fcopy daemon, previously provided by the hypervfcopyd package. The suite of daemons provided by hyperv-daemons are needed when a Linux guest is running on a Microsoft Windows host with Hyper-V.

Several significant enhancements to device-mapper have been introduced in Red Hat Enterprise Linux 6.6:

The device-mapper-persistent-data package now provides tools to help use the new dm-era device mapper functionality released as a Technology Preview. The dm-era functionality keeps track of which blocks on a device were written within user-defined periods of time called an era. This functionality allows backup software to track changed blocks or restore the coherency of a cache after reverting changes.

Broadwell-U PCH SATA, HD Audio, TCO Watchdog, and I2C (SMBus) device IDs have been added for the drivers, which enables support for the next generation mobile platform in Red Hat Enterprise Linux 6.6.

VIA VX900 Media System Processor is supported in Red Hat Enterprise Linux 6.6.

Federal Information Processing Standards Publications (FIPS) 140 is a U.S. government security standard that specifies the security requirements that must be satisfied by a cryptographic module utilized within a security system protecting sensitive, but unclassified information. The standard provides four increasing, qualitative levels of security: Level 1, Level 2, Level 3, and Level 4. These levels are intended to cover the wide range of potential applications and environments in which cryptographic modules may be employed. The security requirements cover areas related to the secure design and implementation of a cryptographic module. These areas include cryptographic module specification, cryptographic module ports and interfaces; roles, services, and authentication; finite state model; physical security; operational environment; cryptographic key management; electromagnetic interference/electromagnetic compatibility (EMI/EMC); self-tests; design assurance; and mitigation of other attacks.

The following targets have been fully validated:

The following targets have been revalidated:

Added functionality of System Security Services Daemon (SSSD) enables better interoperability of Red Hat Enterprise Linux clients with Active Directory, which makes identity management easier in Linux and Windows environments. The most notable enhancements include resolving users and groups and authenticating users from trusted domains in a single forest, DNS updates, site discovery, and using NetBIOS name for user and group lookups.

A set of Apache modules has been added to Red Hat Enterprise Linux 6.6 as a Technology Preview. The Apache modules can be used by external applications to achieve tighter interaction with Identity Management beyond simple authentication. For further information, refer to the description of the target setup at http://www.freeipa.org/page/Web_App_Authentication.

The gdk-pixbuf2 package, previously a part of the gtk2 package, has been added to Red Hat Enterprise Linux 6.6. The gdk-pixbuf2 package contains an image-loading library that can be extended by loadable modules for new image formats. The library is used by toolkits such as GTK+ or Clutter. Note that downgrading the libraries included in the gdk-pixbuf2 and gtk2 packages can fail.

Performance Co-Pilot (PCP) provides a framework and services to support system-level performance monitoring and management. Its light-weight, distributed architecture makes it particularly well-suited to centralized analysis of complex systems.

Performance metrics can be added using the Python, Perl, C++ and C interfaces. Analysis tools can use the client APIs (Python, C++, C) directly, and rich web applications can explore all available performance data using a JSON interface.

For further information, consult the extensive man pages in the pcp and pcp-libs-devel packages. The pcp-doc package installs documentation in the /usr/share/doc/pcp-doc/* directory, which also includes these two free and open books from the upstream project:

http://www.performancecopilot.org/doc/pcp-users-and-administrators-guide.pdf

http://www.performancecopilot.org/doc//pcp-programmers-guide.pdf

New java-1.8.0-openjdk packages, which contain the OpenJDK 8 Java Runtime Environment and the OpenJDK 8 Java Software Development Kit, are now available in Red Hat Enterprise Linux 6.6 as a Technology Preview.