Due to combined use of Debian stretch, that uses systemd by default, and sdwdate (that uses Slow Clock Adjuster ( gh )), my system clock is frequently changed.As a result journalctl -f gets endlessly spammed by.[...]Nov 07 13:46:49 host systemd[766]: Time has been changedNov 07 13:46:50 host systemd[766]: Time has been changedNov 07 13:46:51 host systemd[766]: Time has been changed[...]This was not an issue on Debian wheezy that used sysvinit.How can systemd be configured to not send the Time has been changed message to the journal?A related question How to disable systemd's Time has been changed message spam in /var/log/syslog on Debian jessie? has been solved, but that solution won't work here.
How to disable systemd's Time has been changed message spam in systemd journal while using sdwdate?
systemd
The message comes from src/core/manager.c in the systemd sources. It is hardcoded to use INFO system logging level.By default systemd logs messages that have INFO level, if you can change that by changing /etc/systemd/system.conf to:LogLevel=noticebut you will lose quite a few of other informational messages as well.It might be best to patch src/core/manager.c to read: log_struct(LOG_DEBUG,            MESSAGE_ID(SD_MESSAGE_TIME_CHANGE),            MESSAGE=Time has been changed,            NULL);(LOG_DEBUG is defined as the next higher, and highest level in sys/syslog.h), or comment out the whole message.I haven't found a way to only report timer changes that have a minimum size of X seconds. But if that is possible that would undoubtedly make for a more complex and error prone patch.