when my lab departed for the John Innes Centre about a year ago, there was a large quantity of raw computer parts left behind for the salvage heap. I wanted a dedicated place to back up my laptop and home computers remotely, and had heard about freely-available network attached storage (NAS) systems, but that was where my knowledge ended. Our lab had been using the somewhat pricey synology NAS system, and I wanted to learn if there was an open source alternative.
FreeBSD-based FreeNAS fit the bill. There is a TON of info and support for how FreeNAS works and how to get it going. What I envisioned was taking some old HDDs laying around, reformatting them, and using them as the storage core of the system. I would boot to a usb drive on which I’ve installed FreeNAS, and format things from there. The amazing thing is… it basically worked and now I have a server for a lot of previously unsecure stuff. Booting off of a USB loaded with the OS is actually the recommended way to go: see this simple instructional video from FreeNAS
One detail that is worth noting is that FreeNAS storage is memory intensive. I am not 100% clear on why, but I believe it has to do with the ZFS-based architecture (NB: zfs does not stand for anything!). For each TB of hard drive, they recommend 1GB of RAM, starting with at least 4GB RAM as a base. Luckily I had a bunch of DDR3 RAM laying around and a capable Asus X99 motherboard with an i7 cpu. Once I got the thing running, it had 64GB RAM supporting 8TB of hard storage; I’ve gone about 2TB into this thing after about a year.