Cannot mount RAID-1 hard drive

[CHONG Yu Meng]

Hi all, 

I've been given a NAS that has stopped working, and it appears that the
motherboard is fried. So I take out the hard disks from the NAS which 
were in a RAID-1 (mirrored) array previously, and try to mount them.

And, embarrassingly, I can't seem to get them mounted!

Here's what I did:
1. I booted a PC from a Live CD of OpenSUSE 12.2, launch a terminal
window, connect one of the hard disks via USB, and type this:

linux:~ # parted /dev/sdb print
Model: WDC WD50 00AACS-00ZUB0 (scsi)
Disk /dev/sdb: 500GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   End    Size   Type     File system     Flags
 1      32.3kB  543MB  543MB  primary  linux-swap(v1)  type=82
 2      543MB   499GB  498GB  primary  ext2            type=83

Ok, so I know the data is probably in the second partition, so that
should be /dev/sdb2, right?

2. So, now I create a mount point and try to mount:
linux:~ # mkdir /mnt/hdd0
linux:~ # mount /dev/sdb2 /mnt/hdd0
mount: unknown filesystem type 'linux_raid_member'

Ok, so it was one half of a Software RAID system in the NAS (D-Link
DNS-323). With a previous NAS, I was able to mount by simply specifying
the filesystem type, so:
linux:~ # mount -t ext2 /dev/sdb2 /mnt/hdd0
mount: /dev/sdb2 is already mounted or /mnt/hdd0 busy

3. So now, I am beginning to worry, because I know next to nothing about
Software RAID in Linux. I Google around and I find out that I need to
stop the RAID array, so:
linux:~ # cat /proc/mdstat
Personalities : [raid1]
md127 : active raid1 sdb2[2]
      4999156 blocks super 1.2 [2/1] [U_]

unused devices: <none>
linux:~ # mdadm --stop /dev/md127
mdadm: stopped /dev/md127

4. So, now I try to mount the data partition again:
linux:~ # mount -t ext2 /dev/sdb2 /mnt/hdd0
mount: wrong fs type, bad option, bad superblock on /dev/sdb2,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail or so
linux:~ # mount /dev/sdb2 /mnt/hdd0
mount: unknown filesystem type 'linux_raid_member'

WTH, it's still seen as a "linux_raid_member"! So I check the status of
the software RAID:
linux:~ # cat /proc/mdstat
Personalities : [raid1]
unused devices: <none>

Looks like it is stopped! So, why is the partition still seen as part of
the RAID-1 array?

I'm out of ideas. Can somebody help me out here? Am I doing this
correctly? What else can I do? I need to get the data out of that hard
disk.

Thanks in Advance!
Pascal Chong