Simple Raid-1 setup question

[Kurt Newman <kurt@lamer.org>]

My questions are as follows:

1) If you're creating a completely new array (e.g. raid-1) on new
partitions that aren't formatted, do you still have to sync?  I'm having
difficulty finding information on why and when a sync is needed.  I was
under the impression a sync is only needed when there's existing
information on one or more of the drives.

2) If there used to be information on each device, but has since been
repartitioned, so that new partitions and a raid device can be
created... is there any way to prevent mdadm from asking if you really
want to create the array?  Using `--force' doesn't seem to help.

mdadm: /dev/sda1 appears to contain an ext2fs file system
   size=1464840K mtime=Fri Nov 13:04:09 2009
mdadm: /dev/sdb1 appears to contain an ext2fs file system
   size=1464840K mtime=Fri Nov 13:04:09 2009
Continue creating array?

As a side note, there really isn't an existing ext3 fs on it, but there
used to be.  To re-use the device, I issued the following commands:
 > parted -s /dev/sda mklabel msdos
 > parted -s /dev/sda mkpart primary ext3 0 1500