How do I hibernate in Ubuntu 20.04?

Solution 1:

To enable Hibernation in 20.04 using Swapfile:

Increase swapfile size to match RAM size up to 8GB.

  • Check the swap that is in use:

    sudo swapon -s
    
  • If swap partition(s) are found:

    sudo swapoff -a
    sudo nano -Bw /etc/fstab
    
  • Add # before the UUID of the swap partition(s):

    # UUID=XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX   none   swap    sw     0       0
    
  • Add a line for the swapfile, if one does not exist:

    /swapfile   none    swap     sw      0       0
    
  • Create the swapfile:

    sudo fallocate -l XG /swapfile*
    

    where X is swapfile's size in GB:

    sudo mkswap /swapfile
    sudo chmod 0600 /swapfile
    sudo swapon /swapfile
    
  • Reboot:

    sudo reboot
    

Add resume location and offset to grub.cfg:

  • Edit /etc/default/grub:

    GRUB_CMDLINE_LINUX_DEFAULT="quiet splash resume=UUID=XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX resume_offset=XXXXX"
    
  • Use UUID from root.

  • Use offset from:

    sudo filefrag -v /swapfile |grep " 0:"| awk '{print $4}'
    
  • Update GRUB:

    sudo update-grub
    
  • Test hibernation:

    sudo systemctl hibernate
    

A hibernate button can be added using GNOME extensions.

Note that there is a slight possibility of getting holes in a swapfile when creating it with fallocate. /var/log/syslog can be searched for the phrase swapon: swapfile has holes to ensure there will be no data loss.

A swap file can alternatively be created using dd:

sudo dd if=/dev/zero of=/swapfile bs=1G count=8

An error when using dd may overwrite your HDD.