I set up IDE software-RAID on a test machine for testing the recover functionality. The problem is that it somehow won't boot after removing the first disk, although grub etc. seems to be setup okay. Here's some background:
2 disks hda and hdb RAID 1 setup: /dev/md0 (hda1 + hdb1) /boot /dev/md1 (hda2 + hdb2) / /dev/md2 (hda3 + hdb3) swap
done with disk druid during initial setup from server disk, so far so good. Then I installed grub to hdb. grub-install complained all the time (I may have given it the wrong parameter), so I used grub directly: root (hd1,0) setup (hd1) That's correct, isn't it? (Is there a way to determine if grub is installed on the correct disk?) I added a third boot entry to the grub.conf (see below).
I then removed disk 1 (hda) from the array by unpowering it and rebooted. Unfortunately, that sent me right in the BIOS PXE boot instead of trying the other disk, well, that's a BIOS problem. So I repowered disk 1 and rebooted. The grub on it is still working somehow but just fills the screen with "grub". So I moved disk 2 before disk 1 as a boot device in BIOS and tried again. This time I get a grub prompt. So, grub is obviously correctly installed on it. However, why doesn't it then boot?
When I type in the exact same data that I have in grub.conf it boots. I resynced the disks now, but still can't boot normally.
grub.conf is like this (taken from another non-RAID, full setup grub.conf and adjusted, so it differs cosmetically):
default=0 fallback=2 timeout=10 #splashimage=(hd0,0)/grub/splash.xpm.gz hiddenmenu title CentOS (2.6.9-34.0.1.EL) root (hd0,0) kernel /vmlinuz-2.6.9-34.0.1.EL ro root=/dev/md1 initrd /initrd-2.6.9-34.0.1.EL.img title CentOS-4 Server_CD (2.6.9-34.EL) root (hd0,0) kernel /vmlinuz-2.6.9-34.EL ro root=/dev/md1 initrd /initrd-2.6.9-34.EL.img title CentOS 2 (2.6.9-34.0.1.EL) root (hd1,0) kernel /vmlinuz-2.6.9-34.0.1.EL ro root=/dev/md1 initrd /initrd-2.6.9-34.0.1.EL.img
When I change default to 2 it still doesn't boot, just gets me grub. I then reinstalled grub on the resynced hda with the same commands used earlier (adjusted for it, of course) and rebooted with hda as first boot disk. There's still the same behavior as before: booting from hda gives "grub grub grub ...".
So, none of two boots like it should. disk 1 cannot boot at all, although resynced and disk 2 only manually. What could be the problem?
Kai