OpenFiler originally started out as a series of packages and scripts against FedoraCore, but then became a distribution unto itself, built on top of CentOs, which is in turn based on RedHatEnterpriseLinux. It uses components such as Samba, OpenLDAP and LVM, and ties it all together with a simple web interface. Because of its strong base it will work on almost all hardware you throw it at. With a couple of mouse clicks you can have a file server authenticating off ActiveDirectory or NIS. It also supports acting as an iSCSI initiator and volume snapshots.
The reason OpenFiler spun out into a distro of its own was it was starting to become a bit unruly as a set of packages for Fedora, and you may also find if your requirements involve the box doing anything else, or having any manual configuration, then OpenFiler is not for you. If all you ever need is storage, then this project is a really good way to go.