raid (mdadm / software raid) issues with grub
Playing around on my labrat I realized that sometimes EL/Centos (6.5 when writing this) messes up booting when using Software raid.
When typical stuff like grub-install from a rescue console doesn’t work:
1 2 3 4 5 | # chroot /mnt/sysimage/ # grub-install /dev/sda /dev/md0 does not have any corresponding BIOS drive # grub-install --recheck /dev/sda /dev/md0 does not have any corresponding BIOS drive |
Or trying to boot from /boot (/dev/md0):
# grub-install /dev/md0
Let’s try something else:
grub> root (hd0,0)
root (hd0,0)
Filesystem type is ext2fs, partition type 0xfd
grub> setup (hd0)
setup (hd0)
Checking if "/boot/grub/stage1" exists... no
Checking if "/grub/stage1" exists... yes
Checking if "/grub/stage2" exists... yes
Checking if "/grub/e2fs_stage1_5" exists... yes
Running "embed /grub/e2fs_stage1_5 (hd0)"... 27 sectors are embedded.
succeeded
Running "install /grub/stage1 (hd0) (hd0)1+27 p (hd0,0)/grub/stage2 /grub/grub.conf"... succeeded
Done.
grub> root (hd1,0)
root (hd1,0)
Filesystem type is ext2fs, partition type 0xfd
grub> setup (hd1)
setup (hd1)
Checking if "/boot/grub/stage1" exists... no
Checking if "/grub/stage1" exists... yes
Checking if "/grub/stage2" exists... yes
Checking if "/grub/e2fs_stage1_5" exists... yes
Running "embed /grub/e2fs_stage1_5 (hd1)"... 27 sectors are embedded.
succeeded
Running "install /grub/stage1 (hd1) (hd1)1+27 p (hd1,0)/grub/stage2 /grub/grub.conf"... succeeded
Done.