How to change switch to a different root partition

Question

I am using AWS EC2 instance with Ubuntu 10.04 installed on it. I start with the instace which has its root partition at /dev/sda1. Later I want to attch a new EBS volume at /dev/sdb1 and want to get rid of the volume at /dev/sda1.

I then want to reboot the instance so that after the reboot the instance starts using the volume at /dev/sdb1 as its root partition and I can delete the volume at /dev/sda1.

Can anyone please tell me what commands I need to execute for this.

Answer 1

1. Reconfigure GRUB for the new boot partition:

   info grub

   The GRUB configuration file is /boot/grub/menu.lst. Backup that file.

2. Backup your /etc/fstab and change it to reflect the changes:

   http://en.wikipedia.org/wiki/Fstab

3. Reboot.