I posted here in March speculating when RHEL6 would be released. I’m pleased to say that the final version of Red Hat Enterprise Linux 6 has now been officially released!

Red Hat 5 was getting rather long in the tooth, and I’m sure many users will be happy to see the inclusion of more up to date packages – MySQL 5.1, Python 2.6 and PHP 5.3 amongst the more notable that will have been giving some users of RHEL5 headaches.

Red Hat 6 provides much more than just a version bump to packages though, there are some key changes. KVM is now the default virtualisation technology. Xen is still supported, and RHEL6 will work as a RHEL5 guest out of the box, as long as one uses an ext3 /boot partition. The para-virt drivers for VMWare are also included, making those deployments simpler too.

ext4 is now the default file system, which provides support for file systems up to 1 exabyte in size and files up to 16TB. Red Hat only officially supported file systems of up to 8TB in size on RHEL5, although it was possible to make them larger than this. ext4 also brings much better performance, and removes the limit of 32000 subdirectories in a single directory.

Upstart is now used for the boot process, replacing the old /etc/init.d scripts. Upstart will be familiar to those who have used more recent versions of Ubuntu Linux, where the project was started. It provides support for automatically respawning failed daemons – something that will be music to the ears of anyone who has ever tried to log into a machine that has had the SSH daemon killed by the out of memory killer. It also always for parallel execution of startup scripts, meaning that RHEL6 boots significantly faster than previous versions.

One other piece of good news for sysadmins is that sendmail is now no longer the default MTA – I can almost hear the cheers of readers from here! Postfix is now provided by default, with the distinct advantage of configuration files that are easily distinguishable from line noise.

Overall, Red Hat Enterprise Linux 6 is a massive step forward from the previous version – as you’d expect, given RHEL5 was released in 2007.

red hat, redhat, rhel, rhel6