Mdadm not starting at boot

[Hal Vaughan <hal@thresholddigital.com>]

I have two systems, both freshly installed Sarge systems, both with a RAID 5 
array (3 drives plus a spare each).  One is working perfectly.  The other has 
a problem whenever it boots (and I've had a number of power failures lately).  
When the system boots, the RAID is not started.  I have to run mdrun to start 
the RAID.  Once it's started, when I try mounting it, I always get a message 
that it has a bad superblock.  I have to run fsck, which fixes it, and then I 
can mount it and it works fine.

I tried dpkg-reconfigure and specifically told it to start on boot and to 
start the monitor on boot, but that hasn't helped.  This array, when running, 
is a 290GB RAID, so it takes a long time to fsck and it currently holds 115GB 
of data.

So why won't this RAID restart on boot when the other does?

Thanks for any help!

Hal