Feature request: true RAID-1 mode

Yet another boot loader support request.

Right now btrfs' definition of "RAID-1" with more than two devices is a
bit unorthodox: it stores on any two drives.  "True RAID-1" would
instead store N copies on each of N devices, the same way an actual
RAID-1 would operate with an arbitrary number of devices.

This means that a bootloader can consider a single device in isolation:
if the firmware gives access only to a single device, it can be booted.
 Since /boot is usually a very small amount of data, this is a very
reasonable tradeoff.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.