Comment # 2 on bug 958346 from Bernhard Wiedemann

here are some pointers
https://en.opensuse.org/SDB:Systemd#Getting_debug_from_systemd
http://freedesktop.org/wiki/Software/systemd/Debugging/

also interesting: are the 10 of 50 a truly random selection
or is it always from a smaller pool of machines?
If the latter, it might be worth checking if there is a pattern
standing out (e.g. different hardware, setup or workload)