Software Raid On Boot

Nigel Wade nmw at ion.le.ac.uk
Wed Feb 15 10:16:03 UTC 2006


Rejean Proulx wrote:
> Does software raid work on a boot device? If not, that could be one of 
> my problems. If it does, should grub contain md0?
> 

You can mirror (RAID1) the boot device, but you cannot stripe (RAID0) it.
Grub needs to boot from the "raw" /dev/hda etc. device, it knows nothing about 
software RAID.

This is the grub.conf from a (RHEL AS4) system I setup yesterday with RAID1 
partitions for / and /boot:

#boot=/dev/hda1
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Red Hat Enterprise Linux AS (2.6.9-11.ELsmp)
         root (hd0,0)
         kernel /vmlinuz-2.6.9-11.ELsmp ro root=/dev/md1 rhgb quiet
         initrd /initrd-2.6.9-11.ELsmp.img

/boot is /dev/md0, which comprises /dev/hda1 and /dev/hdd1. / is /dev/md1 which 
comprises /dev/hda3 and /dev/hdd3. GRUB must be installed into the MBR of 
/dev/hda (for some strange reason I had to do this manually on this install). 
GRUB doesn't handle RAID1 all than well, lilo does it better as it understands 
RAID1 and installs the correct MBR on each disk. GRUB is not able to boot from 
/dev/hdd1; if /dev/hda fails I will have to either modify /boot/grub/grub.conf 
and install GRUB in /dev/hdd, or move the disk so it becomes /dev/hda. Because 
of the way lilo works it can install boot sectors on /dev/hda and /dev/hdd, both 
of which will work.

-- 
Nigel Wade, System Administrator, Space Plasma Physics Group,
             University of Leicester, Leicester, LE1 7RH, UK
E-mail :    nmw at ion.le.ac.uk
Phone :     +44 (0)116 2523548, Fax : +44 (0)116 2523555




More information about the fedora-list mailing list