RAID boot
From Smop.co.uk
Due to a broken motherboard I've bought a new motherboard and some more disks to move away from BIOS-level RAID to proper linux software RAID.
partition the disk using cfdisk:
- /dev/sdc1, /dev/sdd1 (100MB, bootable, type=FD (linux raid)) - this will be /boot
- /dev/sdc2, /dev/sdd2 (rest of disks, type=FD (linux raid)) - this will be LVMd into the rest
build arrays:
- mdadm -C --level=1 --name=bootmd /dev/md/0 --raid-devices=2 /dev/sd[cd]1
- mdadm -C --level=1 --name=bootmd /dev/md/1 --raid-devices=2 /dev/sd[cd]2
setup volume group:
- pvcreate /dev/md/1
- vgcreate rootvg /dev/md/1
- lvcreate -L 5G -n rootlv rootvg
- lvcreate -L 1G -n varlv rootvg
- lvcreate -L 5G -n homelv rootvg
create filesystems:
- mkfs.ext3 /dev/md0
- mkfs.ext3 /dev/rootvg/rootlv
- mkfs.ext3 /dev/rootvg/varlv
- mkfs.ext3 /dev/rootvg/homelv
remove root only limts:
- tune2fs -m0 /dev/rootvg/homelv
copy files across:
- mount everything under /mnt
- copy files using "cp -ax"
setup booting:
- chroot /mnt
- edit /etc/fstab appropriately
- create MD raid array information
- mdadm --detail --scan >> /etc/mdadm/mdadm.conf
- rebuild initramfs (with mdadm, fstab information):
- mkinitramfs -o /boot/initrd.img-`uname -r` `uname -r`
- rebuild grub device map:
- mv /boot/grub/device.map /boot/grub/device.map.old
- grub (just quit)
- edit /boot/grub/menu.lst:
- # kopt=root=/dev/rootvg/rootlv ro
- # groot=(hd2,0) (hd3,0) (look at device.map for these values)
- grub-install /dev/sdc
- grub-install /dev/sdd
- reboot and change BIOS to boot off these disks
