What are you using for your "NAS?" I'm currently using an actual NAS (consumer grade, was kinda buggy until about 2 firmwares ago).
I don't actually have anything yet. Waiting for my tax return to get that up and running. Might use this mini-itx case I have here for a homemade one, but depending on how inexpensive and convenient consumer grade all-in-ones are, I might just get one of those instead.
Well depending on your Linux experience you could just toss something together and use software raid, but you'd need space for a few drives (aka no mini-itx).
Or you could just get an actual NAS:
Synology makes great ***, but it's expensive.
I have one of these:
http://www.amazon.com/Cloud-EX4-Diskless-High-performance-reliability/dp/B00G4JZ2T0/ref=sr_1_1?s=electronics&ie=UTF8&qid=1452192042&sr=1-1&keywords=wdex4
I wish I had WD Red drives in it but I have cheap drives in it, but it still functions for what I use it for. If you're just sharing to a computer it works fine.
It has user management and stuff on it too.
My biggest complaint with it (now, after some firmware upgrades to resolve another issue) is that things like the sftp config are locked down and you'd basically have to custom build the firmware to bypass it and yeah...
The thing that was fixed was it kept saying a drive failed when it didn't and I'd have to reset it and retest it fully to get it to clear, but it stopped doing it 2 firmware upgrades ago.
(sorry about the fractured thoughts, I'm running on little sleep).
I went to a full on NAS to avoid having to fiddle with linux so much as I'm still a noob at it, but it just got more frustrating with what I wanted to change, however creating the shares and the users is easy as hell, it technically is supposed to be able to connect to samba but haven't tried it yet).