[TriLUG] Taking apart software RAID

[Greg Cox]

> I have a FC2 box that is running software RAID1 (via md) across two
> drives, and I'd like to dismantle the RAID without a reinstall.

My suggestion would be: make sure you can boot off either mirror (i.e.
GRUB is properly configured on hd0,0 and hd1,0) and the BIOS will seek
either drive if one is missing.

Boot up single user.  swapoff and fail hdc to break the mirror and
run on hdd only.  fdisk hdc, mkfs.  mkdir /newdisk, mount hdc? to
/newdisk so you make the full tree.  copy everything over to /newdisk.
Fix /newdisk/boot/grub/grub.conf, fix /newdisk/etc/fstab.  umount
/newdisk, shut down.

gank hdd, make sure you can boot off hdc in non-RAID.  If you can't,
put hdd back in so you'll boot back up on the halfmirror (you tested
to make sure you can do that, right?)  When you get hdc up as root
by itself, shut down.

Reinstall hdd, start up singleuser, fdisk hdd, mkfs, add hdd to
fstab, rm raidtab, reboot multiuser.  Open beer, toast self.