On Wed, 25 Mar 2015, Scott Sinno wrote:

    JBOD controller failed this morning - we've replaced it, and all
drives are being presented to the system again, however 'mdadm' refuses
to assemble the ARRAY.  I've tried assembling with '--force' flags but
it still won't...any help most appreciated.  I'm guessing I'll need to
recreate with '--assemble-clean'

I would recommend you to not do that unless there is no other way out.

Please post dmesg output from the --assemble --force attempt, it might 
contain reason why the assembly was unsuccessful.

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