Journald is a system service for collecting and storing log data, introduced with systemd. It tries to make it easier for system administrators to find interesting and relevant information among an ever-increasing amount of log messages.
To avoid excessive wear of the limited flash memory on Toradex modules, the journald data is stored in RAM by default. To debug certain aspects such as unexpected reboots, it is handy to activate persistent journald logging, so the log messages of previous boot cycles can be reviewed.
Attention: Please, use this function with caution, as it can decrease the lifespan of your eMMC/NAND due to flash usage for logging.
For more details about each possible parameter to be set for Journald, please consult the Journald Documentation.
d /var/volatile/log 1777 - -
# rm /var/log
# journalctl --list-boots # journalctl -b -1