Hi.

There is a typo on http://www.netbsd.org/guide/en/chap-rf.html#chap-rf-configuring-raid
Just under section 15.3.5. Initializing the RAID Device it says:

# vi /var/tmp/raid0.conf
START array
1 2 0

START disks
/dev/wd9a
/dev/wd1a

Where wd9a should be replaced with wd0a.

Cheers,
Marcin.