Where can I find log messages? How can I set the log level?
In order to reduce the risk of SD corruption, Zynthian image has the file-system log disable by default. Also, by default, the UI runs with a low logging level (warning level).
The recommended way of viewing the log messages is well documented in our wiki:
Simply:
systemctl stop zynthian
/zynthian/zynthian-sys/sbin/zynthian.sh
Also, i highly recommend you take a look to this script 
Of course, you can enable the file-system log by creating the folder “/var/log/journal” like this:
mkdir /var/log/journal
reboot
But be careful: by using this you could easily end with a unusable SD and have to re-burn.
Kind Regards,
Ah, ok, I missed the Wiki page. I guess I’ll try to route the logging to a RAM based destination, that’s how the armbian people keep the SD card from burning out.