xKillerbees - 2014-08-21

I have an existing debian 6 server. I am turning it into a raid-1.

Creating raid 1 array /dev/md1 with devices /dev/sdb5 [#755:mainfunctions]
mdadm --quiet --create /dev/md1 --level=1 -n 2 -x 0 /dev/sdb5 missing [#756:mainfunctions]
mdadm: device /dev/sdb5 not suitable for any style of array
/dev/md1 raid array, failed to be created! [#242:step2]

Here is the lograider tgz
https://drive.google.com/file/d/0B3l8yj4LfrO5bkloYWdjaDBfRnc/edit?usp=sharing

I've done this successfully with several other machines, but this one has stumped me with this error.