CentOS 7 (1511)
CentOS describes itself as "… a stable, predictable, manageable, and reproducible platform derived from the sources of Red Hat Enterprise Linux (RHEL)." CentOS began as an independent project offering something close to the RHEL experience without the hefty licensing fees. Since then, Red Hat has embraced the project and now acts as an official CentOS sponsor. The latest release, CentOS 7, 1511, is based on RHEL 7.2. Highlights of the new release include enhancements for identity management, containers, and software-defined networking.
Rockstor is a specialty Linux distro designed to support Btrfs-based network-attached storage (NAS) devices. You can set up your Rockstor NAS device on commodity hardware, or run Rockstor as a virtual machine on a Xen, KVM, or VMware host. The copy-on-write Btrfs filesystem offers powerful benefits such as built-in support for pooling and snapshots. Rockstor also works well as a private cloud server for home and small-business environments.