Enabling of the hibernation option on Ubuntu 20.04 LTS didn't work in the way I used to do. So, I had to explore further and do it slightly differently. This blog post records those things I did to get hibernation option working.
1. First of all, create a swap file using the following commands.
sudo fallocate -l 17G /swapfile
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile
Once done, add an entry to the end of /etc/fstab file to make use of this swap file as follows.
/swapfile none swap sw 0 0
2. Check the UUID of the partition where the swap file is located using the following command.
cat /etc/fstab
Take note of the UUID string, which we will need in a later step.
3. Check the offset to the swapfile with in the storage device using either of the following commands. Take note of that offset value.
sudo filefrag -v /swapfile | awk '{ if($1=="0:"){print substr($4, 1, length($4)-2)} }'
sudo swap-offset /swapfile
4. Now, open the /etc/default/grub file and add update the correct line as follows.
Original line:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
Updated line:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash resume=UUID=a27fc21e-3315-4497-99aa-1fe7fad64091 resume_offset=9807872"
Note that the UUID value and the resume offset value are found using the above steps 2 and 3.
Once this grub file is updated, run the following command to take the changes effect.
sudo update-grub
5. Test whether the hibernation option is working now, use either of the following commands. I personally prefer the second command as it provides some verbose output while the system is being hibernated and being resumed later.
sudo systemctl hibernate
sudo pm-hibernate
Cheers!
References:
- https://linuxize.com/post/create-a-linux-swap-file/
- https://askubuntu.com/questions/1240123/how-to-enable-hibernate-option-in-ubuntu-20-04
- https://wiki.archlinux.org/index.php/Power_management/Suspend_and_hibernate#Hibernation_into_swap_file
