Kernel patch b2f78e88052bc0bee ("btrfs: allow degenerate raid0/raid10")
in
5.15 will allow mounting and converting to single device raid0 or two
device raid10. Let mkfs create such filesystem.
"The motivation is to allow to preserve the profile type as long as it
possible for some intermediate state (device removal, conversion), or
when there are disks of different size, with raid0 the otherwise
unusable space of the last device will be used too. Similarly for
raid10, though the two largest devices would need to be the same."
Signed-off-by: David Sterba <dsterba@suse.com>
a177ef7dd4