"FreeNAS" to boot from USB memory and change PC to NAS

You can easily make extra machines to NAS. All management is possible from the browser, RAID 0 · 1 · 2 is possible, and support such as Samba, FTP, NFS, UFS, FAT 32, EXT 2 / EXT 3 etc. FreeBSD is the base.

Download from below.
FreeNAS: The Free NAS Server - Downloads

It can be downloaded by ISO image etc.

The official website is below.

FreeNAS: The Free NAS Server - Home
http://www.freenas.org/

It seems that convenience will increase considerably even if Japanese manuals and so on are in place and become Japanese.