3. Virtualization

3.1. Xen

Xen is a high performance and secure open source virtualization framework. Virtualization allows users to run guest operating systems in virtual machines on top of a host operating system. Red Hat Enterprise Linux 5.7 provides the following bug fixes and enhancements for Xen:

The performance of Xen guests in 32-bit domains is improved.
The maximum amount of disks that can be attached to a Xen guest has been increased from 100 to 256.
The time needed to boot Xen guests is reduced.
Xen guests now support up to 4 serial ports.
xz compression support is now available in Xen PyGrub.

3.2. KVM

Red Hat Enterprise Linux 5.7 includes support for the Kernel-based Virtual Machine (KVM) hypervisor. 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.

This release provides the following bug fixes and enhancements:

CD-ROM emulation in KVM is improved.
Live migration convergence speed is improved.
Issues with the boot order of virtual machines have been fixed.