TrueNAS Core - TrueNAS Core (formerly FreeNAS) is a storage operating system strong and robust enough to meet the needs of enterprise level businesses.
StableBit DrivePool - State of the art, file based drive pooling software.
Amahi - Amahi is a media, home and app server software known for its easy-to-use user interface. Amahi has the best media, backup and web apps for small networks.
btrfs - Btrfs is a modern copy on write (CoW) filesystem for Linux aimed at implementing advanced features...
XigmaNAS - File Sharing, OS & Utilities, and Security & Privacy
Greyhole - Greyhole is an application that uses Samba to create a storage pool of all your available hard drives, and allows you to create redundant copies of the files you store, in order to prevent data loss when part of your hardware fails.