5.9 Release Notes

The mstflint package, which provides Mellanox firmware burning and diagnostics tools, now includes support for Mellanox ConnectX-3 devices.

The smartmontools package, which provides tools for monitoring SMART-capable hard drives, has been upgraded to add support for HP Smart Array controllers. This update also adds improved MegaRAID support.

The Dell-specific IPMI extension, which adds the delloem subcommand to the ipmitool utility, has been updated to include the following enhancements:

The NetApp LUN built-in configuration now uses the tur path checker by default. Also the following hardware table parameters have been updated:

The following tracepoints for system call events have been added:

Red Hat Enterprise Linux 5.9 adds hardware checksum support for UDP running over IPv6.

The prlimit64() system call has been added to allow users to dynamically change the limits of a running process via the /proc/<PID>/limits file (this file is now writable).

VLAN support has been added to the pktgen module. The pktgen module is now able to produce 802.1Q tagged frames.

The hidepid= and gid= mount options have been added to procfs to allow restricting of access to /proc/<PID>/ directories.

In Red Hat Enterprise Linux 5.9, the netfilter module now supports mangling of the DSCP field.

This feature allows you to compare a booted system with a dumped system to efficiently analyze changes that might be introduced by image migration. To identify a guest, stsi and stfle data is used. A new function, lgr_info_log() compares the current data (lgr_info_cur) with the last recorded one (lgr_info_last).

The Parallel access volume (PAV) storage server feature is intended to achieve better I/O performance through alias devices. With HyperPAV, you no longer need to configure dedicated aliases for each device for which you want to use PAV with. HyperPAV supports an alias pool from which alias devices are automatically assigned when required. This results in reduced configuration effort and dynamic self-optimization of the PAV configuration.

Applications often use system calls that are related to system time. The virtual dynamic shared object (vdso) support is a kernel-provided shared library that holds the required data for the correct system time. The calculation is done in user space, and accelerates the operations. This results in increased performance, especially for applications with high amounts of time-related system calls.

Red Hat Enterprise Linux 5.9 adds support for using FIPS mode with dmraid root devices. A dmraid device is now activated before the FIPS checksum is checked.

In Red Hat Enterprise Linux 5.9, users are able to migrate from RHN Classic to Red Hat Subscription Asset Manager (SAM). SAM acts as a proxy for handling subscription information and software updates on client machines. For more information on the migration process, refer to the Subscription Management Guide.

Support for the selection of a remote server during the registration of a system is now supported in Subscription Manager. The Subscription Manager user interface provides an option to choose a URL of a server to register against, together with a port and a prefix, during the registration process. Additionally, when registering on the command line, the --serverurl can be used to specify the server to register against. For more information about this feature, refer to the Subscription Management Guide.

In Red Hat Enterprise Linux 5.9, during firstboot system registration, registering to Red Hat Subscription Management is now the default option.

Subscription Manager now disables gpgcheck for any repositories it manages which have an empty gpgkey. To re-enable the repository, upload the GPG keys, and ensure that the correct URL is added to your custom content definition.

System profiles are now unregistered when they are deleted from the Customer Portal so that they no longer check in with certificate-based RHN.

Subscription manager now allows users to associate a machine with a preferred Service Level which impacts the auto-subscription and healing logic. For more information on service levels, refer to the Subscription Management Guide.

Subscription manager now allows a user to select a specific release (for example, Red Hat Enterprise Linux 5.8), which will lock a machine to that release. Prior to this update, there was no way to limit package updates in the event newer packages became available as part of a later minor release (for example, Red Hat Enterprise Linux 5.9).

The Subscription Manager graphical user interface has been enhanced with various changes based on customer feedback.

Red Hat Enterprise Linux 5.9 adds backported support for the maxclassrepeat and gecoscheck options to the pam_cracklib module. These options are used to check the properties of a new password entered by a user and reject it if it does not meet the specified limits. The maxclassrepeat option limits the maximum number of consecutive characters of the same character class (lower case, upper case, digits, and other characters). The gecoscheck option checks whether the newly-entered password contains words (space-separated strings) from the GECOS field in the /etc/passwd entry of the user that is entering the password. For more information, refer to the pam_cracklib(8) man page.

The m2crypto package, which provides a library that allows programs to call OpenSSL functions from Python scripts, has been updated to modify the HTTPS implementation to work with both IPv4 and IPv6. In addition, the M2Crypto.SSL.Connection object can now be instructed to create IPv6 sockets.

The sudo utility is able to consult the /etc/nsswitch.conf file for sudoers entries and look them up in files or in LDAP. Previously, when a match was found in the first database of sudoers entries, the look up operation still continued in other databases (including files). In Red Hat Enterprise Linux 5.9, an option was added to the /etc/nsswitch.conf file that allows users to specify a database after which a match of a sudoers entry is sufficient. This eliminates the need to query any other databases; thus, improving the performance of sudoers entry look ups in large environments. This behavior is not enabled by default and must be configured by adding the [SUCCESS=return] string after a selected database. When a match is found in a database that directly precedes this string, no other databases are queried.

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 5.9 adds support for the IBM iPDU fence device. For more information on the parameters of this fence device, refer to the Cluster Administration guide.

The Distributed Lock Manager (DLM) now allows tuning of DLM hash table sizes from the /etc/sysconfig/cman file. The following parameters can be set in the /etc/sysconfig/cman file:

Integrated Red Hat Enterprise Linux guest installation, and Hyper-V para-virtualized device support in Red Hat Enterprise Linux 5.9 on Microsoft Hyper-V allows users to run Red Hat Enterprise Linux 5.9 as a guest on top of Microsoft Hyper-V hypervisors. The following Hyper-V drivers and a clock source have been added to the kernel shipped with Red Hat Enterprise Linux 5.9:

Red Hat Enterprise Linux 5.9 includes rebased samba3x packages that introduce several bug fixes and enhancements, the most important of which is added support for the SMB2 protocol. SMB2 support can be enabled with the following parameter in the [global] section of the /etc/samba/smb.conf file:

Red Hat Enterprise Linux 5.9 includes full support for OpenJDK 7 as an alternative to OpenJDK 6. The java-1.7.0-openjdk packages provide the OpenJDK 7 Java Runtime Environment and the OpenJDK 7 Java Software Development Kit. OpenJDK 7 includes extensions to support dynamically-typed languages that can run on the JVM, class loader enhancements, support for Unicode 6.0, and updated I/O and networking APIs. OpenJDK 7 is also available in Red Hat Enterprise Linux 6.

The java-1.7.0-ibm and java-1.7.0-oracle packages are now available in Red Hat Enterprise Linux 5.9.

The libitm contains the GNU Transactional Memory Library, which provides transaction support for access to the memory of a process to enable synchronization of access to a shared memory by several threads.

Red Hat Enterprise Linux 5.9 includes a new rsyslog5 package which upgrades rsyslog to major version 5.