How do you backup 24TB of movies?
Technically I don't. And space wise none of the drives are completely full. I have about 6 TB of free space between them.
In the beginning I bought a USB converter cable so I was ripping to "bare" IDE ATA drives. Then I bought a couple NexStar dual drive USB units since all the 2 TB drives are sata. I have one 2 drive "box" with two 2 TB drives connected now but those are each drives I back up data from my iMac. I have data files going back to about 1988 and an old 1400C PowerBook (and an 8500 which runs OS 9 running OS 9 which I can open old OS 9 files with (I still can run MacWrite, MacPaint, SuperPaint, the old Claris programs and *lots* of old OS 9 programs including games and stuff) on and I have a lot of data on 2 TB drives double backed up so in reality I have a lot more than 24 TB of drive space when you include drives with data files.
I've been ripping DVDs for a lot of years. BTW I'm in my 60's and lived through the VHS era, so I copied all my old VHS tapes to video files and gave my old VHS tapes to friends some years back. I started copying/ripping DVDs to 300MB drives. Then when prices came down I switched to 1 TB drives which I copied the 300 MB drives to and "filed" the 300's in the closet. Then when prices came down I switched to 2 TB drives and copied the 1 TB drives to and "filed them in the closet and sold the 300 MB drives I had (18 at the time, if I remember correctly). I have a bunch of 2 TB drives (20 or so) in the closet. Then I bought three OWC Firewire 800 Mercury Elite Pro Qx2 "Enterprise" 12 TB drives and set them up for RAID 5 with parity (which leaves about 8 TB per enclosure) and copied all the 2 TB drives to them and put the old 2 TB drives in the closet. This way I have 3 Firewire 800 (the 3 Mercury drives) drives with media (and 3 other drives with data backups and a Firewire 800 which I dedicated to TimeMachine on my iMac) all connected to my iMac and since all my computers are on my home/office LAN I can get on any computer in the house and *all* my media is right there by logging into my "main" iMac.
If it's not a DVD (in which case the built-in DVD player program is fine for me) I use VLC because (among a few other reasons) I also have an old EyeTV (the last one before they went to HDMI so I can use to record via component video so no DRM issues). So - I've got .mpg files, .mov files, .mp4 files, .avi files, DIVX files, .flv files, etc. VLC plays anything and the remote on my iPhone and iPad work very well. My plan is to buy a Mac-Mini and a 55" TV (probably January 2013) after I buy a new iMac. I have Plex and XBMC on my iMac and have used them, but they're too slow and it's too hard (takes too much time) to navigate to the files I want. VLC is also nice because I can quick and easy drag files from different drives into a Playlist. I'm sure Plex and XBMC have their place, but just aren't what I want. As always, YMMV.
The 3 Mercury Elite Pro Qx2 drives I have now are all sorta set up like a library. I have directories for genres and such, and each drive has specific genres and such. I keep my files pretty well organized.
I'm just an old, retired Mac freak. These days I keep some internet web sites up so I have computer equipment everywhere (PC's and Macs). As you can see, I've been registered here for a while but rarely posted (i.e.: I'm not a "regular" here). I've been waiting for the new iMacs (I have a 2008) to come out so I've been hanging around here waiting for rumors prior to the 23rd. My fingers are crossed that they'll really announce new 27" iMacs.
I'd link to some pictures but I don't really know what the link policy is here so I won't (but you can Google/Bing/DuckDuckGo/whatever for my user name here - It's one of my web sites).
EDIT ADD: My GF likes VLC, too. She can watch videos on a PC I have set up in another room while I am working on my iMac or if I want to watch something different. She's hoping I get a new iMac soon so I can put the PC somewhere else and put my 2008 iMac there because she prefers Mac over PC and she can't play DVDs on the PC which are on my iMac drives. There may be a way that it can be done, but I haven't found a way (and aren't really worried about that). And like me she likes to browse the files in the finder rather than navigate through stuff using Plex or XBMC.