its quite possible I didn't understand what I was doing when I set it up, but...
OK, I bought three 2TB drives that I wanted to use for media storage. I didn't want to deal with figuring out which files to put in which drive, so I Googled "how to span disks" and discovered lvm. Fine, easy enough... so now I have one 6TB "drive" mounted as a ext4 filesystem at /mnt/bigdisk
Everything seems fine, but as I'm now approaching 2TB usage, I started to wonder the following:
1) How is the data being allocated? Does each drive now have 1/3 of 2TB? Or is one almost full? How can I see it?
2) What happens when one (or more) disk is getting near the limit and I add a file large enough that it has to cross disks? An error, or does it just "handle it"?