What's new in Red Hat Enterprise Linux 5.3
Red Hat has released version 5.3, the third update of the Red Hat Enterprise Linux (RHEL) 5 operating system, first introduced in March 2007. In addition to various bug fixes, RHEL 5.3 also offers a number of new features and improvements.
Several improvements affect virtualisation. The x64 version of Xen now supports up to 126 processors and a Terabyte of memory. The paravirtualised network and mass storage drivers for fully virtualised RHEL-5 guest systems have moved into the kernel, and a separate installation is no longer required. Virtio drivers improve the performance of guest systems under the KVM alternative. Features like extended page tables that are included in recent x64 processors are now supported, which is likely to increase the performance of fully virtualised guests.
Red Hat has also improved cluster operation. The distributed Global Filesystem (GFS) 2 is now officially supported, and fencing has been improved in several minor ways. RHEL 5.3 supports the encryption of root and swap partitions. The developers updated a number of system tools, for example the CUPS print server, the rpm and yum package management tools and the SystemTap tracing tool. Red Hat Enterprise Linux now offers the free OpenJDK Java development environment which, according to Red Hat, fully complies with the Java SE 1.6 Compatibility Kit.
The installer now supports the adapter RAID levels 4, 5 and 10 via dmraid, and allows the installation of mass storage media connected via iSCSI. In systems with several network cards it can show which network device is associated with which physical device by making the LED on the card flash. The update to Network Manager 0.7 and an improved CIFS client, which now also allows access to DFS shares on Windows servers, make the network connections of desktop systems more effective. Various new and improved drivers now support a number of 10-GBit cards and other hardware.
Some new features like the support of AIGLX and Compiz for 3D desktop effects still have technology preview status – users may test them, but Red Hat offers no support in case of problems. This category also includes the cryptographic Ecryptfs file system and Ext4, the future standard file system for Linux, as well as the support for 32-bit guest systems on 64-bit hosts and the Trusted Computing Group's (TCG) software stack for accessing a Trusted Platform Module (TPM).
Red Hat Enterprise Linux 5.3 is available in three varieties: The RHEL 5 Advanced Platform, available for x32, x64, Itanium, System p and System z, allows an unlimited number of virtual guests, offers cluster support and runs on computers with any number of CPUs. The RHEL 5 Server is also available for all platforms, but is restricted to four guest systems and two processor sockets, and comes without the cluster package. The RHEL 5 Desktop is available in several varieties with or without virtualisation support, with or without server and development tools and with various hardware limits for x32 and x64 computers.
While upgrading to version 5.3 is possible from RHEL 4.7 and 5.2, Red Hat doesn't guarantee that all user settings will be transferred. The vendor therefore suggests installing from scratch.
Dr. Oliver Diedrich