Dear All;
I am trying to impliment RAID level 0 on RHEL5 but i am facing the following issue.
i am following this link:http://www.spencerstirling.com/computergeek/raid.html

mknod -m 0660 /dev/md0 b 9 0
chgrp disk /dev/md0

after the above two commands when i impliment the following command
mdadm --create /dev/md0 --level=0 --raid-devices=2 /dev/sda1 /dev/sdb1
it gives errors
"mdadm: /dev/sda1 is too small: 0K
mdadm: create aborted"

when i change the above command
mdadm --create /dev/md0 --level=0 --raid-devices=2 /dev/sda /dev/sdb
its gives erros like this
mdadm: /dev/sda is too small: 0K
mdadm: /dev/sdb appears to contain an ext2fs file system
size=156250000K mtime=Thu Jan 1 05:00:00 1970
mdadm: create aborted

whta can be the issue?
i am stuck here

There is no need for this.

Just do this:
1. create 2 partitions
2. make them type fd (Linux Raid autodetect)
3. write config and make rhel reread partition table
Maybe you did not put it as type "fd"?