I would be very grateful for advice on removing all traces of a previous 
mdadm attempt to create a 3-disk RAID 5 setup so that I can try again 
(or give some advice to solve the problem).
Mandriva 2010.0, mdadm v3.0.2
I had apparently created the RAID 5 set using /dev/sda, /dev/sdc, 
/dev/sdd. I could write to it locally but not from the PC that has the 
data I want to protect, but couldn't stop it(some message to the effect 
that the devise was busy? Can't remember).
I therefore re-installed Mandriva 2010.0, used fdisk to create a single 
partition on each of the three disks but was unable to create the array. 
I was very surprised to find that /proc/mdstat appeared to have survived 
the re-install although mdadm appears not to recognise elements of the 
array (See attachment). Furthermore the existence of /dev/sda1 as a 
RAID-type partition appears to cause elements of the Mandriva Control 
Centre to exit abnormally (the program blkid -o udev -p /dev/sda doesn't 
work).
Some RAID expertise would be very welcome!
TIA
Graeme Gemmill