Red Hat's RHEL 6.3 aims at large-scale cloud deployments

With the release of Red Hat Enterprise Linux (RHEL) 6.3, Red Hat has tweaked the enterprise grade Linux distribution to add new capabilities in storage, virtualization, security, scalability, and performance.

"This is one of largest update release to date," said Tim Burke, Red Hat vice president of Linux engineering development. "It has a lot of performance scalability optimizations specifically targeted at virtualized cloud deployments in the data center."

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To improve overall performance, RHEL 6.3 features a new technology called NUMAD (Non-Uniform Memory Alignment Daemon). NUMAD is based on ideas behind NUMA (Non-Uniform Memory Architecture), a memory management technology developed for supercomputers with large-scale distributed memory. NUMAD will align data in working memory so it is most easily accessible by the processor working on the data.

"The way memory is wired on the chips, data is closer to access from some CPUs than from others," Burke explained. "It takes a lot of smarts from the OS to balance the workloads." Typically, an OS will move the jobs to least-used CPUs, with no regard to where the corresponding data is located. The distance between the CPU and an inconveniently located memory location slows system performance as a whole. NUMAD monitors the system at runtime and watches for memory usage patterns. "It will dynamically balance the workload to balance for both memory and CPU optimizations," Burke said.

The company has added a number of new features and enhancements to aid in virtualization. A new tool, called Virt-P2V, can package all the software running on a server into a virtual machine, so it can run on the KVM (Kernel-based Virtual Machine) hypervisor. It can translate either RHEL of Microsoft Windows environments into virtual packages.

This release also improves RHEL's scalability. Virtual machines running on RHEL 6.3 can now run 160 virtual CPUs (vCPUs), a boost from the limit of 64 in the previous version. Now a single virtual machine can take up to 160 CPUs on a given server. Virtualizing such large workloads can ease the process of moving them from server to server, Burke explained. The memory per KVM guest has also been upped to 2TB from 512GB.

The release also improves security. For example, the new version of the software complies with Payment Card Industry Data Security Standards (PCI-DSS) for deleting no-longer-need virtual machines from servers. It also has been prepared to work with the new, stronger AES-CTR (Advanced Encryption Standard Counter Mode) cipher, which will be used for RHEL's OpenSSH (OpenBSD Secure Shell). AES-CTR is particularly well-suited for high-speed networking environments. In addition, RHEL 6.3 supports two-factor authentication. Administrators can set up RHEL servers so they require not only a password but also a public key as well.