wiki-system/add-right-fit-swap-for-laptop-hibernation-during-ubuntu-20.04-full-ZFS-install.md

create swap partition to permit Hibernate

create a swap partition right sized for hibernation.

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

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

like bellow :

	# 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.

source : Linsomniac's Articles - Encrypting ZFS on Ubuntu 20.04