I was wondering why my system clock was "so damn wrong". A quick check with systemctl status openntpd.service showed me "Active: inactive (dead) since ...". An other "journalctl -xfn" on the command line and "fatal: bad privsep dir /var/lib/ntp permissions: 40755" was marked red.
Searching on the web was, well, some kind of helpful. An old (asian?) entry was the highest in the ranking. After that, I searched on the official repository on github.com and found this patch (full patch view).
After that, it was an easy one to get openntpd back on track. chown -R root /var/lib/ntp and to be on the save side chmod -R 700 /var/lib/ntp followed by systemctl restart openntpd.service and my clock was back on track :-).
So, this is a short story telling about the journey of an arch linux installation on an HP 2530p.
The mission was clear, GPT, LVM and LUKS. The problem was the BIOS in the HP 2530p.
To keep it short, don't trust the documents, simple install a hybrid gpt/mbr), or follow my howto.
The so called documented UEFI boot is only working with windows but not with other UEFI systems. If you simple install a GPT without a hybrid MBR, you won't get a working system disk.
So I'm having this problem on three machines. I've also done the advice "udevadm hwdb --update" but the error still exists on the next boot.
Good thing about it, all is still working. My machines have a "hwdb.bin" file in "/etc/udev/hwdb.bin". I found a bug report on the arch linux bug report list as well as one on the systemd bug report list but no solution.
I will update this entry when I've found a solution or if the error disappears on one of the upcomming updates.