# right fit swap for laptop hibernation Ubuntu 20.04 full ZFS install
## sources

* [rephlex.de - How to hibernate and resume from swap file in Ubuntu 20.04 using full disk encryption](https://rephlex.de/blog/2019/12/27/how-to-hibernate-and-resume-from-swap-file-in-ubuntu-20-04-using-full-disk-encryption/)
* [doc.ubuntu-fr.org - Comment activer l'hibernation](https://doc.ubuntu-fr.org/tutoriel/activer_hibernation)
* [help.ubuntu.com - Enable Hibernate With Encrypted Swap](https://help.ubuntu.com/community/EnableHibernateWithEncryptedSwap#Preparation)
* [tlbdk.github.io - encrypted swap on Ubuntu 18.10](http://tlbdk.github.io/ubuntu/2018/10/22/encrypted-swap.html)

## bios setup

You have to disable secure boot in bios to permit Hibernate because of *kernel lockdown prevent hibernation* see links bellow :

* [stackexchange - Why does the kernel lockdown prevent hibernation?](https://unix.stackexchange.com/questions/591488/why-does-the-kernel-lockdown-prevent-hibernation)

## create swap partition to permit Hibernate

create a swap partition right sized for hibernation.

add theses 2 lines in : */usr/share/ubiquity/zsys-setup*

~~~{.shell}
MEMSIZE=$(cat /proc/meminfo | grep MemTotal | awk -F' ' '{print $2}')
SWAPVOLSIZE=$(( MEMSIZE / 1024 ))
~~~

like bellow : 

~~~{.shell}
    # Convert to MiB to align the size on the size of a block
	SWAPVOLSIZE=$(( SWAPSIZE / 1024 / 1024 ))
    
MEMSIZE=$(cat /proc/meminfo | grep MemTotal | awk -F' ' '{print $2}')
SWAPVOLSIZE=$(( MEMSIZE / 1024 ))

	prepare_target "${TARGET}"
	format_disk "${DISK}" "${PARTBASE}" "${PARTESP}" "${PARTBPOOL}" "${PARTRPOOL}" "${SWAPVOLSIZE}"
	init_zfs "${TARGET}" "${DISK}${PARTBASE}${PARTBPOOL}" "${DISK}${PARTBASE}${PARTRPOOL}"
	init_system_partitions "${TARGET}" "${DISK}${PARTBASE}1" "${DISK}${PARTBASE}${PARTESP}"
~~~

Run ubiquity to start the installer and install as normal, selecting “Use entire disk” and the option to use ZFS.

## activate hibernation in system
Disable secure boot in bios to permit Hibernate.

~~~
apt install pm-utils
~~~

~~~
printf "RESUME=UUID=$(blkid | awk -F\" '/swap/ {print $2}')\n" | head -n 1| sudo tee /etc/initramfs-tools/conf.d/resume
~~~

you can check with : *blkid*

~~~
update-initramfs -u -k all
~~~

change /etc/default/grub : add your resume UUID into GRUB_CMDLINE_LINUX_DEFAULT

~~~
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash resume=UUID=75034ff5-...-9e4564e16d34"
~~~

## enable hibernate in system

/etc/polkit-1/localauthority/50-local.d/com.ubuntu.enable-hibernate.pkla

~~~
[Réactive hiberner par défaut dans upower]
Identity=unix-user:*
Action=org.freedesktop.upower.hibernate
ResultActive=yes

[Réactive hiberner par défaut dans logind]
Identity=unix-user:*
Action=org.freedesktop.login1.hibernate;org.freedesktop.login1.handle-hibernate-key;org.freedesktop.login1;org.freedesktop.login1.hibernate-multiple-sessions;org.freedesktop.login1.hibernate-ignore-inhibit
ResultActive=yes
~~~

## configure hibernate to auto switch from sleep to hibernate

source : [Linux Mint Forums : Enable Hibernation with LUKS on LVM and extras](https://forums.linuxmint.com/viewtopic.php?t=287015)

edit : */etc/systemd/sleep.conf*

And add this value to it (The number represents seconds you want to pass in sleep, after which the computer will switch to hibernation, so you can put it in 60 seconds or something short just to check it's working and after that you can put whatever ammount of time you want):

~~~
[Sleep]
HibernateDelaySec=1200
~~~

Here I choose 1200 for 20min, I think that I can move from one place to an other in less than 20min if it's more systeme goes to hibernate mode.

Modify this two lines in /etc/systemd/logind.conf for sleep key and closing the lid actions if that's how you want it:

~~~
HandleSuspendKey=suspend-then-hibernate
HandleLidSwitch=suspend-then-hibernate
~~~

Now ajust /etc/fstab to use your mapper, replace your swap UUID device to :

~~~
/dev/mapper/swapDevice   none   swap   discard   0   0
~~~

## encrypt swap partition

~~~
apt-get install ecryptfs-utils
swapoff -a
cryptsetup luksFormat --cipher aes-xts-plain64 --verify-passphrase --key-size 256 /dev/nvme0n1p2
cryptsetup open /dev/<device> swapDevice
mkswap /dev/mapper/mkswap /dev/mapper/swapDevice
~~~

edit : /etc/default/grub

~~~
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash resume=/dev/mapper/swapDevice"
~~~

~~~
update-grub
~~~

### to be solve

~~~
cryptsetup: ERROR: Couln't resolve device rpool/ROOT/ubuntu_...
cryptsetup: WARNING: Couln't determine root device
~~~

## xfce4-power-manager suspend to hibernate option

source : [docs.xfce.org - Frequently Asked Questions - Xfce4 Power Manager](https://docs.xfce.org/xfce/xfce4-power-manager/faq)

Because it's not possible to configure suspend-then-hibernate for Lid close inside XFCE Power Manager Control Panel, you will make logind handle button events instead of xfce4-power-manager.

* To have logind handle the lid open/close event

~~~
xfconf-query -c xfce4-power-manager -p /xfce4-power-manager/logind-handle-lid-switch -n -t bool -s true
~~~

If you want everything time related, then you can set them with settings in /etc/systemd : **sleep.conf** and **logind.conf**