I want to have in my network small, cheap and energy efficient server with will be fully customizable (Gnu/Linux, OpenBSD). What is more I want to have big, redundant storage in my network and access to it via server. I have already small terminal without hard drive (no SATA/PATA, one drive on USB) which works fine. I don't want to buy big server, or to use regular computer for that. It's not cheap.

I thought about a small case (ITX?), and cheap computer in this with SATA ports, but I cannot find anything interesting :(

I thought about NAS in network and server independently and booting server from NAS, I'm not sure which technologies will be good for that, and I don't know what with performance. Direct connection to NAS through network from workstation is next pro for that.

What do you think about DAS? It will be good for that?