On 09/18/2010 05:13 PM, Matthew Topper wrote: > 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 > was gone. > > 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: > > default=0 > timeout=5 > splashimage=(hd0,0)/grub/splash.xpm.gz > title CentOS (2.6.18-194.e15) > root (hd0,0) > kernel /vmlinuz-2.6.18-194.e15 ro root=/dev/VolGroup00/LogVol01 > initrd /initrd-2.6.18-194.e15.img > > 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. http://wiki.centos.org/HowTos/CentOS5ConvertToRAID#head-fa2b73a28acdf965daa1e018962eaa8cbd94110c HTH, Timo :)