StableBit DrivePool - State of the art, file based drive pooling software.
XigmaNAS - File Sharing, OS & Utilities, and Security & Privacy
btrfs - Btrfs is a modern copy on write (CoW) filesystem for Linux aimed at implementing advanced features...
TrueNAS Core - TrueNAS Core (formerly FreeNAS) is a storage operating system strong and robust enough to meet the needs of enterprise level businesses.
Drive Bender - Drive Bender, class leading storage pooling technology
PetaSAN - PetaSAN is an open source Scale-Out SAN solution offering massive scalability and performance.