it is not possible to change uuid of a swap partition with tune2fs, because it only supports ext3/ext4.
you will have to recreate it and pass the uuid during creation, which is not a problem because usually swap SHOULD not contain any valuable data.
mkswap -U 410f0b20-edca-4db2-a8f6-3e82d29602e7 /dev/sda5
If your swap device uuid changes you will have to update several other config files:
- god knows what else
it happened to me, that dmesg showed me that it got stuck for 30seconds during boot by not finding the uuid of swap in /etc/fstab or resume
vim /etc/grub # remove quiet in order to get some output during boot and debug what is happening and where it gets stuck. GRUB_CMDLINE_LINUX_DEFAULT="quiet" update-grub2; # do not forget to run after changes
so it is probably wiser to just restore the existing uuid, when you zeroed out the harddisk (in order to make a backup that saves some space)
how to zero out swap space, before backup:
# where is my swap? swapon NAME TYPE SIZE USED PRIO /dev/sda5 partition 7.7G 0B -1 # what uuid does swap have? blkid /dev/sda5 /dev/sda5: UUID="410f0b20-edca-4db2-a8f6-3e82d29602e7" TYPE="swap" PARTUUID="9c1c254e-05" # label it as swap tune2fs /dev/sda5 -L swap # deactivate swap swapoff /dev/sda5; # overwrite swap partition with zeroes that compress well with gzip time dd if=/dev/zero of=/dev/sda5 bs=$((1024*1024)); # maybe also zero out root partition/harddisk time dd if=/dev/zero of=/fill_up_space bs=$((1024*1024*1024)) count=$((10*9999));rm -rf /fill_up_space; # recreate swap mkswap -U 410f0b20-edca-4db2-a8f6-3e82d29602e7 /dev/sda5 # activate swap swapon /dev/sda5 # check how much swap is used (nill) free -m total used free shared buff/cache available Mem: 7678 725 6501 94 450 6630 Swap: 7876 0 7876
now you can run the backup:
boot/buy from my stick and attach external usb harddisk to save backup file to.
lsblk; # where is what umount /dev/sda*; dd if=/dev/sda | pv | gzip -c > /media/user/BACKUPS/Debian94.img.gz;