My solution:
I had so many DVDs and Blurays (legit ownership) that the wife was too frustrated to watch anything (before streaming was really a thing). She said DO SOMETHING WITH ALL THAT!!! So, I started with a Dlink media player stereo unit, but you had to re-encode everything to mpeg-2, and I would lose my DVD special features and stuff (which, being old school, I want to keep). A friend of mine said "just ISO 'em!" so I found Slysoft. Next, I purchased a trio of Patriot 4 bay NAS'... (I think 1x DN4300 and 2x DN4600). Then one day, I decided to upgrade from 2TB to 4TB drives. The way these NAS' worked, you basically would have to download them to your computer, upgrade 1x drive at a time, and then copy it back and I was running on 1Gbe and hardwired ethernet. It took a couple of weeks. Well, I started looking to upgrade to 6TB drives a short while later and said no way in hell I'm doing that whole copy down, upgrade copy back thing again, so I tried putting the drives from the NAS into a repurposed rig with Ubuntu Server. Ubuntu server could read my oldest Patriot 4 bay NAS drives as RAID drives, but the 2x newer Patriots, couldn't be read. I found out, in order to read the new Patriot NAS drives on a Linux system, I would need to recompile the Linux Kernal into a special block size to be able to read those drives from that NAS. WHAT??? That means getting Linux source code and the like. So let me get this straight... If my Patriot (white) units go bad, I'd really have no way to access the drives and things would be lost. NO, this is not sustainable. Ditching the Patriot NAS', I upgraded the repurposed rig (mobo, proc, memory) from a Core 2 Quad to a core i7-4770K (dual purposed as a Virtual Box server) with PCI 3.0 2x 16 port Avago adapters in IS mode (HBA mode). Transferred a test to the computer. I streamed, at the same time, 2x bluray ISOs, 1 HD MP4, and 2 DVD ISOs from the computer to 5 different machines in the house and I was only using about 1GB of RAM and about 75% of one of the 4 cores of the Core 2 Duo (I later upgraded to the core 2 quad, but really didn't need to, and then to the 4770K, and given that Bluray is up to about 25Mbps, and DVDs are up to about 5Mbps bit rate, my hard wired network in the house had ZERO issues streaming and the server handled it just fine on a 7200RPM Maxtor drive. I've since upgraded that server rig (like I mentioned), and I have SSD as a boot device, SSD as a Virtual Box image drive, and ISOs/MP4s on HDDs (5400 and 7200 RPM drives - 7200 because got a good deal, Enterprise drives, brand new) and then have some spares that I used to take backups of all I have. I mean, think about it, no need to have a live mirror because the data is 99% static - it will never change once it's there.
The sheer volume of what I have, and what I came from, there's no way discs would work anymore. For me, it's a server and HDDs all the way. I'm not running plex. Just good ol' fashion ISO and Windows/Linux/Mac media players. I am eyeing KODI as a possible interface upgrade, but haven't decided yet. Now that being said, there is a price factor here. Disc media is probably cheaper, in the short term, but disc media has a max recommended life (I think DVD was 11 years depending on how it was kept (environment) ). So 1) all the discs burned would have to reburned at some point; 2) you would have to have backups on disc or HDD - if disc, those too would have to replaced at some point due to age of the media; 3) Switching between the potential volume of media makes this unreasonable in my opinion (not poopooing on others solution, kudos you found something that worked for you). HDDs will fail too over time and have to be replaced. The bigger the drive, the more potential for loss, but I keep backups on additional HDDs. Also, I have the HDDs on the server in a side case external to the server. In an emergency, unplug a few cables, and take the case with the drives and you are good.
Best of luck to you all.
db