Changes to grub in ubuntu 10

grububuntu-10.04

I've been running CentOS 5 for some years. I've decided to upgrade to Ubuntu, and with 10.04 just out, this seemed like a good time.

I'm a tad paranoid, so I started off with a new set of drives – one to install on, one to backup to, and one as a spare. I removed my existing CentOS 5 drives, and did an install, and had no problems. I installed the server version, and used the default full-disk LVM installation.

Next, I copies my backup scripts over, edited them to work with the new configuration, and did a test backup. That worked fine, as well. Then comes the real test, could I do an install of the backup onto the spare drive? (I won't put anything of importance on a system that doesn't have a reliable backup, and if I've never done a restore, it's not reliable.)

I booted from a System Rescue CD (ver 1.5.3), with the spare drive as /dev/sda, and the backup drive as /dev/sdb. I had no trouble in partitioning, configuring LVM, formatting, making swap, or restoring the file systems. But when I got to restoring grub to the MBR, I ran into problems.

My restore instructions from CentOS 5 said run grub, then enter two commands:

root (hd0,0)
setup (hd0)

The first command exits with an error: "Checking if /boot/grub/stage1 exists … no"

I did some googling around, and found that the Grub2 included in recent Ubuntus is very different than the Grub 0.97 included in CentOS 5. One site suggested I use:

grub-install –root-dir=/mnt/restore /dev/sda

That appeared to work, but when I booted from the drive, I ended up at a grub prompt.

Any ideas as to what I need to do? It seems like a simple problem, but my attempts at searching out answers on the web are being swamped by references to the old version of Grub.

Help would be appreciated.

Best Answer

My restored drives had all of the proper grub installation and configuration on them, it was just a matter of getting things to where I could execute them.

I booted off the Ubuntu install CD, selected "rescue", and then set my new root directory as the root directory, and started a shell in that directory.

I then mounted /boot, and ran update-grub and grub-install, and everything worked fine.