Ubuntu hard drive upgrade

I just finished upgrading the hard drive on my Ubuntu machine, and it wasn’t as easy or straightforward as I was expecting.  So I figured I’d write up some notes for the next time I do it.

First I backed everything up. Then I shut down the computer, put the new drive in, and booted up with a copy of Knoppix I had lying around. Under Knoppix, I opened up a shell and mounted my old root filesystem:

# mount /dev/hda1 /mnt

I then mounted the new root filesystem on /mnt2, and copied all the files over:

# mount /dev/hdb1 /mnt2
# cd /mnt
# tar cvpf - . | (cd /mnt2; tar xpf -)

Then, I installed the grub boot loader in the MBR of the new drive:

# grub
# root (hd1,0)
# setup (hd1)

At that point, I shut down the computer, removed the old drive, installed the new one in its place, and attempted to boot back up. Happily, it found the grub boot loader and proceeded to load the kernel. But then it hung trying to mount the root filesystem.

It turns out that a couple releases ago, Ubuntu started referring to disk partitions by UUID rather than using a specific device name such as /dev/sda1 or /dev/hda1. Both /boot/grub/menu.lst and /etc/fstab still contained UUID references for the old hard drive, so I had to go through and painstakingly replace all the old UUID references with the updated UUID for the new disk. I just used vi and did a search-and-replace, although there’s probably an easier way. Once I did this, everything booted up just fine.

I can see the advantages to using UUIDs, but it does add an extra layer of complexity when doing something like this. At least I know what to expect the next time around.

Coming soon: my adventures upgrading from Ubuntu 7.04 (Feisty Fawn) to 7.10 (Gutsy Gibbon).  There were a couple of snags, but it was mostly painless.