- The RHEL 6.3 kernel contains the Net_prio Cgroup controller that was integratedin Linux 3.3; administrators can use this technology, which is also known as Network Priority Cgroup Infrastructure, to set network interface priorities for Control Group (Cgroup) processes.
- The new "numad" background service, which is currently a Technology Preview, is designed to optimise the use of system resources in systems with a non-uniform memory architecture.
- The SSH daemon can now request multiple types of authentication from users – not just either a password or a public key, but both. Further additions include new centralised administration features for SSH keys.
- As an alternative to OpenJDK 6, Red Hat has included OpenJDK 7 as a Technology Preview.
- MySQL's InnoDB plugin can now be used on x86-64 systems; the plugin is said to offer a greater number of features and better performance than MySQL's integrated InnoDB storage engine.
- Rsylogd has made a version jump to series 5.
- The system's Linux Container (LXC) support, and the Btrfs filesystem that is still considered experimental in Kernel.org kernels, continue to be classified as Technology Previews in RHEL 6.3; Oracle and SUSE have officially supported both technologies in their own enterprise distributions for about three months.