livebackup

Simply create a bootable squashfs live systems from your running Linux

This is a bash script designed to create a bootable squashfs file from either an installed Linux system or the live system itself. It's an adaptation of the "Live Ubuntu Backup" script originally authored by billbear@gmail.com. I've simplified its code, concentrating solely on live system backups and ensuring it functions for more than just Ubuntu; it supports any Debian-based Linux distribution.

The squashfs backup file can be booted directly using GNU grub:

 menuentry "GNU/Linux in SQUASHFS IMAGE (Live CD mode, read only)" {
	set gfxpayload=keep
	insmod probe
	insmod squash4
	set file="/backup.squashfs"
	search --no-floppy -f --set=SFSROOT  $file
	probe -u --set=SFSUUID ${SFSROOT}
	loopback loop (${SFSROOT})/$file
	set root=${SFSROOT}
	linux (loop)/boot/vmlinuz root=UUID=${SFSUUID} squashfs=$file rw quiet splash locale=en_US.UTF-8 acpi_backlight=vendor
	initrd (loop)/boot/initrd.img
 }

Alternatively, you can manually restore the squashfs backup to a physical hard drive partition or a disk image file:

MOUNT YOUR HD PARTITION OR DISK IMAGE FILE (eg. /VirtualBox/linux.vhd ) TO /mnt,

 cd /mnt
 sudo unsquashfs /backup.squashfs
 sudo mv squashfs-root/* ./
 sudo rm -rf squashfs-root

EDIT fstab, change the root file system type and root partition UUID:

 sudo vi ./etc/fstab

And then boot from it. Here is an example of a grub.cfg configuration for booting from a VHD file:

 menuentry "GNU/Linux in VHD IMAGE (Hard disk mode, read and write)" {
	set gfxpayload=keep
	insmod probe
	set file="/VirtualBox/linux.vhd"
	search --no-floppy -f --set=SFSROOT  $file
	set root=${SFSROOT}
	probe -u --set=SFSUUID ${SFSROOT}
	loopback loop (${SFSROOT})/$file
	linux (loop,msdos1)/boot/vmlinuz root=UUID=${SFSUUID} kloop=$file kroot=/dev/mapper/loop0p1 rw quiet splash locale=en_US.UTF-8 acpi_backlight=vendor
	initrd (loop,msdos1)/boot/initrd.img
 }

Boot squashfs live system from unpartitioned disk area:

menuentry "GNU/Debian Linux 12" --unrestricted {
	set gfxpayload=keep
	set file="/backup.squashfs"
	linux /efi/debian/vmlinuz root=HIDDENPART=9805c7f3-a88d-49c6-8cc2-28f170c36609+10967056384+53687091200 rootfstype=btrfs rootsubvol=Debian squashfs=$file rw quiet splash locale=en_US.UTF-8 initramfs.runsize=50%
	initrd /efi/debian/initrd.img
}

In this example, we specify root=HIDDENPART=diskuuid+offset+sizelimit, where "diskuuid" is a disk identifier that can be found using the "fdisk" utility; "offset" is the data start offset in bytes into the specified disk area; and "sizelimit" marks the end of the data after the start. For more details, see the man page for losetup. Here, we use the command sudo losetup -o 10967056384 --sizelimit 53687091200 /dev/loop8 /dev/sdc to map an unpartitioned disk area to /dev/loop8. We then format /dev/loop8 as Btrfs, create a subvolume named "Debian", and copy backup.squashfs into it. Now, we can boot our Debian live system from this "empty", unpartitioned disk area.

Thanks to

• "Live Ubuntu Backup" script originaly written by billbear@gmail.com
• "kloop" scripts written by niumao