Also got this when I entered: cat /proc/mdstat

paul@paul-System-Product-Name ~ $ cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
unused devices: <none>
paul@paul-System-Product-Name ~ $

Don't know if that helps?

hmmm...

try this:

Then put the output of this:

This will give a clue as to whether or not you have a MB RAID.

Based on the "df" output, it looks like you have a 1.8 TB device of some sort. This could well be your RAID (try the commands suggested by lsalab to be sure). Does the size match up with what you were expecting your RAID device to be? Based on the output of "cat /proc/mdstat", it's certain you do not have any software RAID arrays defined.

This is all I get when I input your suggestions (~ $ dmraid -r), and ~ $ sudo apt-get install dmraid:

paul@paul-System-Product-Name ~ $ ~ $ sudo apt-get install dmraid
bash: /home/paul: Is a directory
paul@paul-System-Product-Name ~ $ ~ $ dmraid -r
bash: /home/paul: Is a directory
paul@paul-System-Product-Name ~ $

Yes, I do have two, 2TB drives in the tower (they were my previous RAID array set-up), in addition to the 128G SSD just for the Linux install; that still has 98Gigs free on it, because I don't use it for anything else.
Just so you know, every time I boot up the computer, I now have to "mount" the 2TB drive in order to access my stuff. Before it used to mount automatically when I booted up. Not a big deal, just thought I'd mention it. When I click on "Home" (the SSD Home), it only shows one 2TB volume under "devices".

OK, you misunderstood my previous post.

The '~ $' is actually your prompt, not part of the command itself. Just execute the commands without the '~ $'

This will install the 'dmraid' command:

and then, you can execute the command: