had this RHEL 5 installation with /dev/sda1 and /dev/sda2 running..
created two more partitions /dev/sdj1 and /dev/sdj2 , the same sized partition as /dev/sda
trying to use mdadm to create RAID1 ..
I cannot even do it in "rescue" mode, I wonder if it can be done..
it kept complaining /dev/sda1 is open or busy..
It probably means what it says. If the partition's mounted, part of another raid, or otherwise occupied, it's busy.
What, exactly, are you doing? Tell us word for word, letter for letter, keystroke for keystroke.
The output of fdisk -l and cat /proc/mdstat would also be useful.
had the system configured and booted with /dev/sda1 and /dev/sda2..
trying to do raid1 using mdadm on these 2, as an after thought ..
How can it be done ??