Install CachyOS on ZFS

Partitioning

$ lsblk --output NAME,FSTYPE,LABEL,PARTTYPENAME,SIZE,MOUNTPOINT
NAME        FSTYPE     LABEL     PARTTYPENAME          SIZE MOUNTPOINT
nvme0n1                                                3.7T
├─nvme0n1p1 vfat       EFI       EFI System              1G /boot/efi
├─nvme0n1p2 vfat       Boot      Microsoft basic data    3G /boot
└─nvme0n1p3 zfs_member zpcachyos Linux filesystem      3.7T

• https://wiki.archlinux.org/title/GRUB/Tips_and_tricks#Recall_previous_entry

GRUB_SAVEDEFAULT=true will only work if /boot/grub is not on btrfs / ZFS, because GRUB cannot write to btrfs / ZFS.

How to disable zram?

• https://askubuntu.com/a/1419240

# /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="systemd.zram=0"

Specifying boot ID has no effect, no persistent journal was found.

• https://discourse.practicalzfs.com/t/psa-systemd-journal-persistence-settings-and-race-condition-between-zfs-mount-service-and-systemd-journald-service/1929

With your persistent journal being stored on a ZFS filesystem, there is now a race condition on startup beween zfs-mount.service, which will mount your /var/log directory, and systemd-journald.service, which will try to write to it before it’s been mounted. This can cause systemd-journald to fall back to using an in-memory journal, or result in unpredictable loging behaviour

The fix is to create a dependency for systemd-journald.service on zfs-mount.service:

# /etc/systemd/system/systemd-journald.service.d/zfs.conf
[Unit]
After    = zfs-mount.service
Requires = zfs-mount.service