Cloning file system

⇐ Notes

to clone file system

use dd to clone disk, e.g.

sudo dd if=/dev/sda of=/dev/sdb bs=4M conv=noerror,sync status=progress

to mount clone

principle is that the cloned volume needs to renamed before it can be mounted

rename volume

sudo vgimportclone --basevgname ubuntu-vg-clone /dev/sdd3

activate

sudo lvchange -a y 'ubuntu-vg-clone/ubuntu-lv'

mount

sudo mount /dev/sdb1 /media/USB/sdb1

sudo mount /dev/sdb2 /media/USB/sdb2

sudo mount /dev/mapper/ubuntu--vg--clone-ubuntu--lv /media/USB/sdb3

to boot from clone

the principle is to change uuid of disks and modify grub.cfg files to reflect this. There appears to be a grub.cfg in both /boot/efi (which is separate VFAT partition on my system) and in /boot/grub (which is the ext4 boot partition). Note that the external disk is listed as /dev/sdb when we have booted normally. If we attempt to boot from the external disk it will be listed as /dev/sda

to find current uuids a number of commands show them

sudo blkid

lists the physical uuids of the disks

sudo pvdisplay

sudo vgdisplay

sudo lvdisplay

will display the lvm physical and logical groups and logical volumes respectively

modify uuid of /dev/sda1 which will be mounted as /boot/efi

not sure how to do this reliably as yet - but probably doesn't matter

modify uuid of /dev/sda2 which will be mounted as /boot

sudo uuidgen

to generate and display a new random uuid number

sudo tune2fs -U <new_uuid> /dev/sdb2

where <new_uuid> is the new uuid displayed earlier

edit grub.cfg on /boot/efi

sudo emacs /boot/efi/EFI/ubuntu/grub.cfg

& change the line

search.fs_uuid 96b8896d-0474-48c4-9976-f71e754b7ca4 root hd0,gpt4

and insert the new uuid generated previously