Enabling Hibernate on Linux

Hibernate saves the entire contents of RAM to disk and powers the machine off completely; powering back on restores the session exactly where it was left, with no battery drain in between (unlike suspend-to-RAM). For it to work, three things need to be true: swap must exist, swap must be at least as large as RAM, and the kernel needs to be told where to find it at boot. The exact steps differ slightly between Debian-based distros and Fedora.

Debian-based Distributions (ubuntu, Mint, Pop!_os)

Check swap and RAM:

swapon --show
free -h

If swapon --show prints nothing, swap needs to be created first — see the swap-file guide.

Find the swap UUID:

blkid

/dev/sda3: UUID="xxxx-xxxx" TYPE="swap"

Configure GRUB to tell the kernel where to resume from:

sudo nano /etc/default/grub

Change:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

to:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash resume=UUID=YOUR_SWAP_UUID"

Apply and test:

sudo update-grub
systemctl hibernate

Fedora

Fedora uses Dracut instead of initramfs-tools, so rebuilding the initramfs is a separate, explicit step.

swapon --show
blkid

Edit GRUB:

sudo nano /etc/default/grub

GRUB_CMDLINE_LINUX="resume=UUID=YOUR_SWAP_UUID"

Rebuild the GRUB config — the path differs between BIOS and UEFI systems:

# BIOS
sudo grub2-mkconfig -o /boot/grub2/grub.cfg

# UEFI
sudo grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg

Rebuild the initramfs so Dracut knows about the resume device:

sudo dracut -f

Test:

systemctl hibernate

Troubleshooting

Check whether the kernel reports hibernate support at all:

cat /sys/power/state

If disk appears in the output, hibernate is supported. If it fails to resume, check the boot log:

journalctl -b

Note

• Swap must be large enough to hold the full RAM contents — undersized swap is the most common cause of a failed resume.
• A swap file works, but a dedicated swap partition tends to be more reliable for resume-from-hibernate.
• Secure Boot can occasionally interfere with the resume process; if hibernate silently fails to resume, that's worth ruling out.