[kwlug-disc] Bundling HD's. LVM vs mdadm vs ???

[unsolicited]

I'm running out of backup space, so I'm probably going to buy a larger 
drive, and move a current drive into another computer - expecting to 
bundle it with the drive already there into a single logical 
presentation. (Add 4TB, move 2TB -> 2TB + 2TB = 4TB.)

I don't 'do' RAID (at least at home, where high availability isn't an 
issue), and mistrust striping - lose 1 drive, both be gone. I prefer to 
say 'this' amount of space for 'this' purpose, so when I run out of 
space I'm aware of and address the issue.

(Presumably a worst case scenario for such bundling upon failure is 
losing one file - the one that crosses physical drives. Correct, even 
today?)

I've known for some time LVM is out there, just never needed it. There's 
also mdadm ('LINEAR') [Which I gather LVM calls upon.]

Any particular pros / cons / preferences / suggestions / thoughts for 
bundling multiple drives into a single logical drive?

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I'm guessing the only reasonable drive out there at the moment is a WD 
Black - (5 yr warranty, 7200, SATA3, availability / stock levels). 
Counter suggestions?