On Wed, 9 Nov 2011, William Colls wrote:

Environment

Kubuntu Linux 10.04.3 LTS
mdadm 2.6.7.1-1ubuntu15

I have two identical disks that were in a raid configuration in another 
machine (also running 10.04). I removed them from the old machine, mounted 
them in a new machine, booted up, and at a terminal prompt as root issued

mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdb /dev/sdc

Did you mean create or assemble?

If you used create it would have nuked all the data - including partition 
table and filesystem..

... actually, I don't know the precise mechanism for a create on raid 1 - 
if it just copies one disk to the other, then the data might well be 
intect if you can recover the partition table, but if it writes zeros to 
both disks then you're out of luck ...

Gordon