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Date: Fri, 12 Dec 2014 14:54:24 -0800
From: Robert White <rwhite@pobox.com>
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To: Btrfs BTRFS <linux-btrfs@vger.kernel.org>
Subject: RAID0 extent sizes?
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I've seen it mentioned here that generally data extents are 1G and 
metadata extents are 256M.

Is that per-drive or per-stripe in the case of RAID0?

That is, if I have data mode raid0 across N drives does the system 
allocate one 1G extent on each drive making the full stripe allocation 
N-gigs; or does it allocate 1/Nth(gig) on each drive making the total 
new allocation 1G?

Does the raid0 have any arity constraints (like how raid1 is always 
arity-2)?