I remembered reading about this once, and researching once before, but
I am pretty sure my Xubuntu 13.10 distro doesn't have the flavor of
mdadm I need.  (Awesome work on this tool Neil! With mdadm you have
transformed the utility of the md subsystem, and made it almost
impossible to break an array with bad options)

I did "--replace" on a 12.04 LTS with a 3.8 kernel plus side-compiled 
mdadm.

-- 
Mikael Abrahamsson    email: swmike@swm.pp.se