Changing the Enclosure ID is the answer.
I have expanded my md3600f with an md1200. The md3600f is showing as Enclosure 0 and the md1200 is showing as Enclosure 3. Clearly Enclosure 3 can't be right since there are only 2 enclosures. How do I rename the enclosure to be 1? Thanks.
Expansion ID and Enclosure Name