[CentOS] Software RAID + LVM + Grub
topperm9 at gmail.com
Sat Sep 18 11:13:08 EDT 2010
I'm playing with software RAID and LVM in some virtual machines and
I've run into an issue that I can't find a good answer to in the docs.
I have the following RAID setup:
md0: sda1 and sdb1, RAID 1. This is /boot
md1: sda2 and sdb2, RAID 1. This is a PV for LVM.
VolGroup00, this is the volume group and md1 is the only PV in it.
LogVol00 is swap
LogVol01 is /
LogVol02 is /home
So, I tested to see what happens if I disable sdb in virtualbox.
Machine booted find and I was able to see that part of the raid array
I reattached the disk and rebuilt the array
mdam --add /dev/md0 /dev/sdb1
mdam --add /dev/md1 /dev/sdb2
The array rebuilt without issue. But now, if I remove sda, the machine
doesn't boot and grub complains. The question I have is how does one
reinstall the boot sector at this point? I'm a little confused as far
as to what device to install it on and what to specify as the root.
This is grub.conf if it helps:
title CentOS (2.6.18-194.e15)
kernel /vmlinuz-2.6.18-194.e15 ro root=/dev/VolGroup00/LogVol01
Grub has always been a little confusing for me, so I guess I don't
understand. What do the two root entries specify? And again, my main
question is how do I reinstall grub to the repaired disk? Sorry for
the lengthy post, I'm trying to provide as much information as possible.
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