[PLUG] Need mdadm help

[John Jason Jordan]

Back in the days when Hardy was the reigning desktop distro I built
myself a new desktop computer. I used two matching 320 GB drives and
set them up as four partitions with RAID 1 (mirror) using mdadm. I wish
I hadn't done that. Now I wish remove one of the drives, in effect, undo
the RAIDs. Unfortunately it has been about three years since I created
the RAID and now I can't make heads or tails of the mdadm man page. I
must have been a lot smarter three years ago.

Worse, I upgraded Hardy to Intrepid, and during the dist-upgrade the
boot information was written to only one of the disks. I can boot, but
only if I scroll down in the Grub menu and choose the previous kernel.
Trying to boot to the current kernel gives me a Grub error 15. I have
ignored this problem for a long time because the computer gets rebooted
only if there is a power failure. This means that if I want to preserve
the existing installation I have to figure out which partition (SDA1 or
SDB1) has the correct boot information.

There are four arrays:
	SDA1 and SDB1 - 45 GB EXT3 boot and /
	SDA2 and SDB2 - 2 GB swap
	SDA3 and SDB3 - 20 GB EXT3 unused
	SDA4 and SDB4 - 235 GB EXT3 old data, unneeded

1) For starters, how can I figure out the names I gave the arrays?

2) Once I know the names of the arrays I might be able to figure out
how to remove one partition from each array, but how can I figure out
which one (between SDA1 and SDB1) has the correct boot information?

I hope someone can help me figure out what I did and how to change it.