On Nov 24, 2007 12:20 PM, Bill Davidsen [off-list ref] wrote:

Does that match what's in the init files used at boot? By any chance
does the information there explicitly list partitions by name? If you
change to "PARTITIONS" in /etc/mdadm.conf it won't bite you until you
change the detected partitions so they no longer match what was correct
at install time.

According to the man page, using 'partitions' as your DEVICE should
cause mdadm to read /proc/partitions and scan all partitions listed
there.  The sda*/sdb* partitions were in /proc/partitions (at least
after the machine fully booted) but for some reason when mdadm
assembled the array it was not adding those partitions.  Changing the
DEVICE to '/dev/hd* /dev/sd*' rather than 'partitions' resolved the
issue.