I would look at the
Synology website products to determine what you need and can afford.
Best NOT to just throw in old HDDs, best to buy a new good quality drive(s) depending on your budget and needs.
so, right now I have a video folder in my pc with about 400gb of videos, stored in a 1tb hdd. it's just sitting there, no redundancy, no external access, nothing. I don't need much more than that, I just need to be able to stream these videos from any device, and eventually put a new vid or two into this folder. if I could simply do that from my pc and not spend a lot on energy bills I would, but I have a power hungry cpu and a 750w power supply, and leaving it on all the time isn't an option. so that's why I need a nas, why exactly you wouldn't recommend to just take that hdd and put into a nas?
I have a 4 bay Qnap TS-453a, for exactly that purpose (and more)
https://www.amazon.com/QNAP-Professional-Grade-Attached-Supports-TS-453A-4G-US/dp/B017YB7T6U
QNAP designs and delivers high-quality network attached storage (NAS) and professional network video recorder (NVR) solutions to users from home, SOHO to small, medium businesses.
www.qnap.com
4x 4TB Seagate Ironwolf drives.
Rock solid, 24/7 since Jan 2017.
I would not hesitate for another Qnap, or Synology, or Theacus. All pretty similar.
As a test, I tried the following:
Playing video out to 3 systems, music to a 4th, while receiving large data transfer (full drive backups) from 2 other systems.
Simultaneously.
Nary a hiccup.
this sounds great, but probably too overkill for me. I don't think I'll ever need more than 1tb of network storage, and if I do, I can just replace the hdd instead of having a multi bay nas.
just so you know, what I currently have is a 32gb usb flash drive plugged into my wifi router. if it worked as it should, I wouldn't even consider buying a nas, I could just keep my files in my computer, and transfer to the usb drive whatever I thought I would watch that week or so, shouldn't need much more than those 32gb. but it doesn't work, transfer speeds are inconsistent, and terribly slow, I think I've never seen it go faster than 3Mbps.
streaming is also bonkers, a different workaround on every device to make it work, and it's never smooth, in many cases, it buffers more than it plays.
so that's why I need a nas, I was hoping I could spend less than 100 bucks to have basic functionality and storage, and decent quality streaming. if not possible, then not much more than 100, but around that price, you know, as cheap as possible, as long as it works.
btw, anyone ever used those buffalo linkstation nas?