RAID1 arrays don't have a chunk size, but if you ever convert
one to RAID5 you will need at least a small one >= 4K.
So round of size to a multiple of 64K.
This only affect Create, not "--grow --size=max". The latter
is too hard and with smaller returns.
Signed-off-by: NeilBrown <neilb@suse.de>
This seems more appropriate for current (and recent) model drives than
64K.
64K is still the default for '--build' as changing that could corrupt
data.
64K is also the default rounding for 'linear' on kernels older than
2.6.16.
Signed-off-by: NeilBrown <neilb@suse.de>
NeilBrown