[gentoo-user] installation / grub boot problem

[Heping He]

Hi, I tried to install gentoo on my AMD 64 dual core machine. It has four
500 GB HDs. I followed the instruction on
http://www.gentoo.org/doc/en/gentoo-x86+raid+lvm2-quickinstall.xml. I
replaced /dev/md4 with raid5 instead of raid0. Here is the list of each HD's
partitiion:

/dev/sda:
partition #,  boot   start    end     type
1                  *        1        18     fd
2                           19       361   fd
3                            362     end  fd

/dev/sdb
partition #,  boot   start    end     type
1                           1        361     82
2                           362     end    fd

/dev/sdc is the same to /dev/sda, and /dev/sdd = /dev/sdb

I created /dev/md1, /dev/md3 and /dev/md4:
mknod /dev/md1 b 9 1
mknod /dev/md3 b 9 3
mknod /dev/md4 b 9 4

and then form raid:
mdadm --create /dev/md1 --level=1 --raid-devices=2 /dev/sda1 /dev/sdc1
mdadm --create /dev/md3 --level=1 --raid-devices=2 /dev/sda2 /dev/sdc2
mdadm --create /dev/md4 --level=5 --raid-devices=4 /dev/sda3 /dev/sdb2
/dev/sdc3 /dev/sdd2

/dev/sdb1 and /dev/sdd1 forms the swap space

mount:
mount /dev/md3 /mnt/gentoo
mount /dev/md1 /mnt/gentto/boot

/dev/md4 is for lvm2 and /usr, /home,  /opt and other common unix dir are
created there

after chroot and emerge, I issued emerge grub and modified
/boot/grub/grub.conf

default 0
timeout 10

title gentoo
root (hd0,0)
kernel /boot/kernel root=/dev/md3

and issue grub
grub> root (hd0,0)
....
grub> setup (hd0)
....
grub> root (hd2,0)
.....
grub> setup (hd2)
.....
grub> quit

When I reboot, the kernel issued a panic msg: it says can't read /dev/md/3
or (hd2,0) is invalid device.

Any idea what went wrong?

Thanks in advance for any suggestion.

--HH