Working on getting RHEL virtual appliances setup in the Amazon cloud this is how you resize the root filesystem after taking a snapshot of the original, creating a larger EBS from the snap, removing the old /dev/sda and attaching the EBS volume you just created.

1. Verify that the device /dev/sda is where the / filesystem resides
   1. # df -h
2. Verify that the device /dev/sda is larger than the usable space
   1. # fdisk -l
3. Open fdisk with /dev/sda specified
   1. # fdisk /dev/sda
4. Delete the current partition
   1. Command (m for help): delete
5. Create a new primary partition
   1. Command (m for help): n
   2. p
   3. Partition number (1-4): 1
6. Use the entire disk for the new partition
   1. “enter”
   2. “enter”
7. Verify that the only thing that has changed on /dev/sda is the size
   1. Command (m for help): p
8. Write out the new configuration
   1. Command (m for help): w
9. Reboot
   1. reboot -n
10. Extend the file system
    1. # resize2fs -p /dev/sda1
11. Verify that the disk size and usable size are the same
    1. fdisk -l
12. Enjoy!

I have had success using a similar method in Ubuntu, but then you have to be careful to leave the boot area and removing the swap partition first. Take a screenshot of fdisk -l /dev/sda before you start mucking around – you’ll be glad you did 🙂

–Nat