Greetings ... Been lurking on the list for some time, hoping that at some point, I might be able to add to the collective (Yes, way to much StarTrek in the background! ) ... I have learn quite a bit by just lurking, but now I think I might have something to add ... I'm not sure the exact protocol or procedure for this and it's late in the evening and would like get this out, before I forgot or lose my cool ... Sorry ... First, in SoftwareRAIDonCentOS5, I would like to suggest a third option, to updating or running grub ... My motivation for a third option, is that hand typing or coping and paste line for line into grub, could lead to cross-eyed mistakes ... So, a simple copy and pasting of the complete bash mini script, would be a little less error prone ... as follows ... grub --no-floppy <<EOF device (hd0) /dev/sdb device (hd1) /dev/sda root (hd0,0) setup (hd0) device (hd0) /dev/sda device (hd1) /dev/sdb root (hd0,0) setup (hd0) EOF One other suggest, devices removed from older raid setup, might need the metadata remove, with the following ... This gave me hell for many days ... mdadm --zero-superblock /dev/sdc1 and/or mdadm --zero-superblock /dev/sdc The last suggestion I have, is to do with copying the partition layout from one device to another ... First in single steps ... Can also be used as a backup of the partition layout for later use ... sfdisk -d /dev/sda > sda.out to dump the partition layout ... sfdisk /dev/sdb < sda.out Or in a single step ... sfdisk -d /dev/sda | sfdisk /dev/sdb I can't remember where I got all these details, so I can really give credit where it's due, this is just info that I have collected over time ... I hope this is useful. Thanks Mailed LeeT P.S. I have been toying with an alternate procedure for converting an ext3 partition on a block device to an ext3 partition on a RAID1 device ... If anybody interested before linux-raid comes back to me, just let me know and I will forward what I have been working on.