I'm interested in setting up something to act as a file server. Think of it as "the cloud" but local. I've never built (or bought) something specifically for this, so it's a big foreign to me.
I think really all I would want is something that can store a lot of TB of data easily. It doesn't need to be fast. It doesn't need to be able to stream media anywhere. It really only needs to be able to act as an SFTP server, maybe run sync thing (new to that), and maybe act as a NAS. My gut feeling is something like 10+ TB might be a good amount to start. Something that won't fill up quick and that I can put big things in (like a full system image of another computer) without concern.
What would be a good way to go about this? Building a computer like normal but getting very cheap stuff? Getting something pre built or used (like surplus office stuff)? I'm just not really sure where to begin.
If you just want a rotational drive array, aren't looking for easy hot-swappability, I'd just start with an ordinary mid-tower case. You can get a 10TB+ rotatational drive today, so all you actually need is space for one 3.5" drive, which is not a lot to ask.
If you're pretty sure that you're gonna stick more 3.5" drives in there, just look for cases that have a bunch of slots for 'em.
If you need more drives than your motherboard has onboard SATA connectors, then you can get a controller card to add more.
If you want to expand later beyond what the tower can store, you can get USB drive arrays.
I personally do not think that used drives are a great idea. There are lots of pieces of computer hardware that can last a very long time, but rotational drives are going to be on the shorter lifetime of hardware that goes. If the company that got rid of them doesn't want them, that's because they don't want to mess with them. I also don't think that you're going to save much if we're just talking about a 10TB server.