Openfiler is an excellent bundle of free and open source applications knit together to create an "instant" cross-platform NAS/SAN (network attached storage/storage area network) server. It is meant to run stand-alone, and thus is a complete package that includes the CentOS Linux operating system. Installation couldn't be easier: Just pop the CD in and go.
Openfiler is a free download and currently has two versions: the stable 1.x release and the 2.0 beta. The former weighs in at 450 megabytes, while the latter is a considerably slimmer 310 megabytes. Openfiler installs on any x86 or x64 computer, from that dusty old desktop PC taking up space in a closet to a high-performance tower or rackmount unit.
Openfiler supports all major network storage protocols: CIFS, NFS, HTTP/DAV, FTP, and iSCSI. Thus, it supports Unix network filesystems, Windows Active Directory and NT4 domains, and Webdav, as well as plain ole' ordinary FTP and the new iSCSI protocol, which allows direct access to storage drives. Openfiler supports LDAP-based single-sign on and authentication and comes with logical volume management for easy storage management.
Openfiler has a polished Web-based administration interface. From it, you can create and manage shares, set quotas, and monitor activity.
Be sure to read the installation notes first, as several pitfalls can befall the unwary. Openfiler is both free of cost and Free software, but commercial support is available for it. Visit Openfiler.com for downloads, forums, and administration manuals.