I raised the issue on the ML but got no reply, so I'm assuming it's a systemd bug. Quoting myself:

I tried booting with systemd and two custom hooks I have that create the
/var directory on tmpfs didn't work. Google doesn't help here and my
experience with systemd is in its infancy, so is there specific action I
should take?

My custom hooks are set to run during sysinit_postmount and
shutdown_preumount, see attached file for full source.


Thanks in advance,
Dimitris


--- Custom hooks in /etc/rc.d/functions.d/

function varsync_start ()
{
# Assuming that we mounted /var as tmpfs in the previous step
stat_busy "Rsyncing /var-sync/ to /var/"
/usr/bin/rsync -ax /var-sync/ /var/
stat_done
}

function varsync_stop ()
{
# saving the /var filesystem from the tmpfs
echo -e 'y\ny' | /usr/bin/pacman -Scc >/dev/null
stat_busy "Rsyncing /var/ to /var-sync/"
/usr/bin/rsync -ax --delete /var/ /var-sync/
stat_done
}

add_hook sysinit_postmount varsync_start
add_hook shutdown_preumount varsync_stop