systemd[1]: Failed to start Create Volatile Files and Directories. - on Arch Linux having zfsonlinux as root
I just got the following entry on my boot up today:
systemd[1]: Failed to start Create Volatile Files and Directories.
After a while of searching using my favorit searchengine, I (as usual

The solution is given in the manpage of the tmpfiles.d.
tmpfiles.d(5) wrote:
If the administrator wants to disable a configuration file supplied by the vendor, the recommended way is to place a symlink to /dev/null in /etc/tmpfiles.d/ bearing the same filename.
So all you have to do is:
sudo su
cd /usr/lib/tmpfiles.d
cp journal-nocow.conf journal-nocow.conf.bak
rm journal-nocow.conf.bak
ln -s /dev/null journal-nocow.conf
And thats it. Fingers crossed you system will boot without errors.