1.2 Notable New Features

1.2.1 Xen Improvements
1.2.2 Notable New Features Available with the Red Hat Compatible Kernel

This release of the Unbreakable Enterprise Kernel includes the following new functionality:

1.2.1 Xen Improvements

Several improvements have been incorporated to support Xen usage with the Unbreakable Enterprise Kernel:

  • Numerous bug fixes and performance improvements.

  • Added support for more than 128 GB in a PV guest.

  • Xen Machine Check Exception (MCE) driver added (allows you to view MCE events that the Xen hypervisor receives).

  • Xen Physical CPU (PCPU) driver added (allows management tools to online or offline physical CPUs in dom0).

  • Xen Processor Aggregator Device (PAD) added (enables configuration and control of all processors on a platform).

1.2.2 Notable New Features Available with the Red Hat Compatible Kernel

The following sections detail notable new features in this update for the Red Hat Compatible Kernel.

1.2.2.1 LVM RAID10 Support

You can create, resize, and remove RAID10 volumes in LVM, where striping is laid out across an array of mirrors.

To create a RAID 10 logical volume, use the following form of the lvcreate command:

# lvcreate --type raid10 -m mirrors -i stripes -L lv_size -n lv_name vol_grp

For example, the following command would create a 200 GB RAID10 volume named myr10vol with four stripes and two mirrors in the myvg volume group:

# lvcreate --type raid10 -m 1 -i 4 -L 200G -n myr10vol myvg

The -m option specifies the number of additional copies of the data, not the total number of copies.

1.2.2.2 New Boot and Kickstart Options

The following new boot options are available:

bond=bondname:bondslave1[,bondslave2]...:[opt1[, opt2]...]

Specifies the bonded network interface, the network connections to be bonded to the interface, and any additional options.

vlanid=tag

Specifies a network device's numeric 802.1q tag to allow installation over a VLAN.

The following new Kickstart options are available with the network keyword:

--bondslaves=bondslave1[,bondslave2]... --bondopts=opt1[, opt2]...

Specifies the network connections to be bonded to the network interface, and any additional options.

--vlanid=tag

Specifies a network device's numeric 802.1q tag to allow installation over a VLAN.

The new Kickstart fcoe keyword allows you to enable Fibre Channel over Ethernet (FCoE) devices in addition to Enhanced Disk Drive Services (EDD) discovered devices. The following options are available with the fcoe keyword:

--autovlan

Specifies that VLANs should be discovered automatically.

--dcb=setting1[,setting2]...

Specifies settings for Data Center Bridging (DCB).

--nic=device

Specifies the name of the FCoE device to activate.

1.2.2.3 Persistent Device Naming

udev maintains persistent device names for devices such as /dev/sdb by creating symbolic links such as /dev/disk/by-path/pci-0000:00:0d.0-scsi-1:0:0:0 and /dev/disk/by-uuid/e8d40553-43f2-4ae6-8e4b-38e04e7ee41c. The kernel message log now records each udev persistent device name mapping in the following format:

udev-alias: device_name (udev_persistent_name1 udev_persistent_name2 ... )

You can use a log analyzer to examine these messages, which are also saved in /var/log/messages.

1.2.2.4 PMU Support for Uncore and Load Latency

The uncore feature of the perf event subsystem implements Performance Monitoring Unit (PMU) support for the Intel Xeon Processor X55xx and X56xx processor families. Multiple processor cores can share physical uncore subsystems, including the L3 cache. Uncore PMU support allows packages to collect performance data, including load latency at various levels in the cache and memory hierarchy, which ranges from micro-operation dispatch up to globally observable data. Debugging in perf is made possible by the implementation of PMU event parsing.